feat: Add multi-language support (i18n)

Languages supported (8):
- English (en)
- 日本語 (ja)
- Deutsch (de)
- Français (fr)
- Español (es)
- 简体中文 (zh-CN)
- 繁體中文 (zh-TW)
- 한국어 (ko)

Changes:
- Add locale column to users table
- Add SetLocale middleware for automatic locale detection
- Add LocaleController for language switching
- Create language files with translations for all UI elements
- Add language selector to user profile page
- Update all Blade views to use translation strings

src/app/Http/Controllers/LocaleController.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Http\Middleware\SetLocale;
+use Illuminate\Http\Request;
+use Illuminate\Support\Facades\Auth;
+
+class LocaleController extends Controller
+{
+    /**
+     * Update the user's locale preference.
+     */
+    public function update(Request $request)
+    {
+        $validated = $request->validate([
+            'locale' => ['required', 'string', 'in:' . implode(',', array_keys(SetLocale::SUPPORTED_LOCALES))],
+        ]);
+
+        $locale = $validated['locale'];
+
+        // Save to user record
+        Auth::user()->update(['locale' => $locale]);
+
+        // Also save to session for immediate effect
+        $request->session()->put('locale', $locale);
+
+        return redirect()->route('profile.edit')->with('success', __('messages.settings.language_updated'));
+    }
+}

src/app/Http/Middleware/SetLocale.php

@@ -0,0 +1,54 @@
+<?php
+
+namespace App\Http\Middleware;
+
+use Closure;
+use Illuminate\Http\Request;
+use Illuminate\Support\Facades\App;
+use Illuminate\Support\Facades\Auth;
+use Symfony\Component\HttpFoundation\Response;
+
+class SetLocale
+{
+    /**
+     * Supported locales
+     */
+    public const SUPPORTED_LOCALES = [
+        'en' => 'English',
+        'ja' => '日本語',
+        'de' => 'Deutsch',
+        'fr' => 'Français',
+        'es' => 'Español',
+        'zh-CN' => '简体中文',
+        'zh-TW' => '繁體中文',
+        'ko' => '한국어',
+    ];
+
+    /**
+     * Handle an incoming request.
+     *
+     * @param  \Closure(\Illuminate\Http\Request): (\Symfony\Component\HttpFoundation\Response)  $next
+     */
+    public function handle(Request $request, Closure $next): Response
+    {
+        $locale = config('app.locale', 'en');
+
+        // Check authenticated user's preference
+        if (Auth::check() && Auth::user()->locale) {
+            $locale = Auth::user()->locale;
+        }
+        // Check session (for immediate effect after changing)
+        elseif ($request->session()->has('locale')) {
+            $locale = $request->session()->get('locale');
+        }
+
+        // Validate locale
+        if (!array_key_exists($locale, self::SUPPORTED_LOCALES)) {
+            $locale = 'en';
+        }
+
+        App::setLocale($locale);
+
+        return $next($request);
+    }
+}

src/app/Models/User.php

@@ -22,6 +22,7 @@ class User extends Authenticatable
         'email',
         'password',
         'is_admin',
+        'locale',
     ];
 
     /**

src/bootstrap/app.php

@@ -14,6 +14,11 @@
         $middleware->alias([
             'admin' => \App\Http\Middleware\AdminMiddleware::class,
         ]);
+        
+        // Add SetLocale middleware to web group
+        $middleware->web(append: [
+            \App\Http\Middleware\SetLocale::class,
+        ]);
     })
     ->withExceptions(function (Exceptions $exceptions): void {
         //

src/database/migrations/2025_11_29_024457_add_locale_to_users_table.php

@@ -0,0 +1,28 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::table('users', function (Blueprint $table) {
+            $table->string('locale', 10)->default('en')->after('is_admin');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('users', function (Blueprint $table) {
+            $table->dropColumn('locale');
+        });
+    }
+};

src/lang/de/messages.php

@@ -0,0 +1,117 @@
+<?php
+
+return [
+    // Navigation
+    'nav' => [
+        'dashboard' => 'Dashboard',
+        'knowledge_base' => 'Wissensdatenbank',
+        'profile' => 'Profil',
+        'user_management' => 'Benutzerverwaltung',
+        'logout' => 'Abmelden',
+        'login' => 'Anmelden',
+        'register' => 'Registrieren',
+    ],
+
+    // Documents
+    'documents' => [
+        'title' => 'Dokumente',
+        'new_document' => 'Neues Dokument',
+        'edit_document' => 'Dokument bearbeiten',
+        'edit' => 'Bearbeiten',
+        'delete' => 'Löschen',
+        'save' => 'Speichern',
+        'cancel' => 'Abbrechen',
+        'created_by' => 'Erstellt von',
+        'updated' => 'Aktualisiert',
+        'path' => 'Pfad',
+        'last_modified' => 'Zuletzt geändert',
+        'no_documents' => 'Keine Dokumente gefunden',
+        'search_placeholder' => 'Dokumente suchen...',
+        'create_success' => 'Dokument erfolgreich erstellt!',
+        'update_success' => 'Dokument erfolgreich aktualisiert!',
+        'delete_success' => 'Dokument erfolgreich gelöscht!',
+        'delete_confirm' => 'Möchten Sie dieses Dokument wirklich löschen?',
+        'linked_references' => 'Verknüpfte Referenzen',
+        'title_label' => 'Titel',
+        'title_placeholder' => 'Dokumenttitel (z.B. Laravel/Livewire/Components)',
+        'title_hint' => 'Tipp: Verwenden Sie Schrägstriche (/) im Titel, um Dokumente automatisch in Ordnern zu organisieren',
+        'content_label' => 'Inhalt',
+        'content_placeholder' => 'Schreiben Sie hier Ihren Markdown...',
+        'saving' => 'Speichern...',
+    ],
+
+    // Quick Switcher
+    'quick_switcher' => [
+        'title' => 'Schnellwechsel',
+        'placeholder' => 'Dokumente suchen...',
+        'no_results' => 'Keine Dokumente gefunden',
+        'navigate' => 'zum Navigieren',
+        'select' => 'zum Auswählen',
+        'close' => 'zum Schließen',
+    ],
+
+    // Admin
+    'admin' => [
+        'user_management' => 'Benutzerverwaltung',
+        'new_user' => 'Neuer Benutzer',
+        'edit_user' => 'Benutzer bearbeiten',
+        'create_user' => 'Benutzer erstellen',
+        'users' => 'Benutzer',
+        'name' => 'Name',
+        'email' => 'E-Mail',
+        'password' => 'Passwort',
+        'password_confirmation' => 'Passwort bestätigen',
+        'password_hint' => 'Leer lassen, um das aktuelle Passwort beizubehalten.',
+        'role' => 'Rolle',
+        'admin' => 'Administrator',
+        'user' => 'Benutzer',
+        'grant_admin' => 'Administratorrechte gewähren',
+        'created_at' => 'Erstellt am',
+        'actions' => 'Aktionen',
+        'edit' => 'Bearbeiten',
+        'delete' => 'Löschen',
+        'no_users' => 'Keine Benutzer gefunden.',
+        'create_success' => 'Benutzer erfolgreich erstellt.',
+        'update_success' => 'Benutzer erfolgreich aktualisiert.',
+        'delete_success' => 'Benutzer erfolgreich gelöscht.',
+        'cannot_delete_self' => 'Sie können sich nicht selbst löschen.',
+        'self_admin_warning' => 'Das Entfernen Ihrer eigenen Administratorrechte sperrt Sie aus dem Admin-Bereich aus.',
+    ],
+
+    // Settings
+    'settings' => [
+        'language' => 'Sprache',
+        'select_language' => 'Sprache auswählen',
+        'language_updated' => 'Sprache erfolgreich aktualisiert.',
+    ],
+
+    // Common
+    'common' => [
+        'save' => 'Speichern',
+        'cancel' => 'Abbrechen',
+        'delete' => 'Löschen',
+        'edit' => 'Bearbeiten',
+        'create' => 'Erstellen',
+        'update' => 'Aktualisieren',
+        'back' => 'Zurück',
+        'confirm' => 'Bestätigen',
+        'yes' => 'Ja',
+        'no' => 'Nein',
+        'loading' => 'Laden...',
+        'error' => 'Fehler',
+        'success' => 'Erfolg',
+    ],
+
+    // Auth
+    'auth' => [
+        'login' => 'Anmelden',
+        'register' => 'Registrieren',
+        'email' => 'E-Mail',
+        'password' => 'Passwort',
+        'remember_me' => 'Angemeldet bleiben',
+        'forgot_password' => 'Passwort vergessen?',
+        'confirm_password' => 'Passwort bestätigen',
+        'already_registered' => 'Bereits registriert?',
+    ],
+];
+

src/lang/en/messages.php

@@ -0,0 +1,117 @@
+<?php
+
+return [
+    // Navigation
+    'nav' => [
+        'dashboard' => 'Dashboard',
+        'knowledge_base' => 'Knowledge Base',
+        'profile' => 'Profile',
+        'user_management' => 'User Management',
+        'logout' => 'Log Out',
+        'login' => 'Login',
+        'register' => 'Register',
+    ],
+
+    // Documents
+    'documents' => [
+        'title' => 'Documents',
+        'new_document' => 'New Document',
+        'edit_document' => 'Edit Document',
+        'edit' => 'Edit',
+        'delete' => 'Delete',
+        'save' => 'Save',
+        'cancel' => 'Cancel',
+        'created_by' => 'Created by',
+        'updated' => 'Updated',
+        'path' => 'Path',
+        'last_modified' => 'Last modified',
+        'no_documents' => 'No documents found',
+        'search_placeholder' => 'Search documents...',
+        'create_success' => 'Document created successfully!',
+        'update_success' => 'Document updated successfully!',
+        'delete_success' => 'Document deleted successfully!',
+        'delete_confirm' => 'Are you sure you want to delete this document?',
+        'linked_references' => 'Linked References',
+        'title_label' => 'Title',
+        'title_placeholder' => 'Document Title (use / for folders, e.g. Laravel/Livewire/Components)',
+        'title_hint' => 'Tip: Use slashes (/) in the title to organize documents into folders automatically',
+        'content_label' => 'Content',
+        'content_placeholder' => 'Write your markdown here...',
+        'saving' => 'Saving...',
+    ],
+
+    // Quick Switcher
+    'quick_switcher' => [
+        'title' => 'Quick Switch',
+        'placeholder' => 'Search documents...',
+        'no_results' => 'No documents found',
+        'navigate' => 'to navigate',
+        'select' => 'to select',
+        'close' => 'to close',
+    ],
+
+    // Admin
+    'admin' => [
+        'user_management' => 'User Management',
+        'new_user' => 'New User',
+        'edit_user' => 'Edit User',
+        'create_user' => 'Create User',
+        'users' => 'Users',
+        'name' => 'Name',
+        'email' => 'Email',
+        'password' => 'Password',
+        'password_confirmation' => 'Confirm Password',
+        'password_hint' => 'Leave blank to keep current password.',
+        'role' => 'Role',
+        'admin' => 'Administrator',
+        'user' => 'User',
+        'grant_admin' => 'Grant administrator privileges',
+        'created_at' => 'Created',
+        'actions' => 'Actions',
+        'edit' => 'Edit',
+        'delete' => 'Delete',
+        'no_users' => 'No users found.',
+        'create_success' => 'User created successfully.',
+        'update_success' => 'User updated successfully.',
+        'delete_success' => 'User deleted successfully.',
+        'cannot_delete_self' => 'You cannot delete yourself.',
+        'self_admin_warning' => 'Removing your own admin privileges will lock you out of the admin panel.',
+    ],
+
+    // Settings
+    'settings' => [
+        'language' => 'Language',
+        'select_language' => 'Select Language',
+        'language_updated' => 'Language updated successfully.',
+    ],
+
+    // Common
+    'common' => [
+        'save' => 'Save',
+        'cancel' => 'Cancel',
+        'delete' => 'Delete',
+        'edit' => 'Edit',
+        'create' => 'Create',
+        'update' => 'Update',
+        'back' => 'Back',
+        'confirm' => 'Confirm',
+        'yes' => 'Yes',
+        'no' => 'No',
+        'loading' => 'Loading...',
+        'error' => 'Error',
+        'success' => 'Success',
+    ],
+
+    // Auth
+    'auth' => [
+        'login' => 'Login',
+        'register' => 'Register',
+        'email' => 'Email',
+        'password' => 'Password',
+        'remember_me' => 'Remember me',
+        'forgot_password' => 'Forgot your password?',
+        'confirm_password' => 'Confirm Password',
+        'already_registered' => 'Already registered?',
+    ],
+];
+

src/lang/es/messages.php

@@ -0,0 +1,117 @@
+<?php
+
+return [
+    // Navigation
+    'nav' => [
+        'dashboard' => 'Panel de control',
+        'knowledge_base' => 'Base de conocimientos',
+        'profile' => 'Perfil',
+        'user_management' => 'Gestión de usuarios',
+        'logout' => 'Cerrar sesión',
+        'login' => 'Iniciar sesión',
+        'register' => 'Registrarse',
+    ],
+
+    // Documents
+    'documents' => [
+        'title' => 'Documentos',
+        'new_document' => 'Nuevo documento',
+        'edit_document' => 'Editar documento',
+        'edit' => 'Editar',
+        'delete' => 'Eliminar',
+        'save' => 'Guardar',
+        'cancel' => 'Cancelar',
+        'created_by' => 'Creado por',
+        'updated' => 'Actualizado',
+        'path' => 'Ruta',
+        'last_modified' => 'Última modificación',
+        'no_documents' => 'No se encontraron documentos',
+        'search_placeholder' => 'Buscar documentos...',
+        'create_success' => '¡Documento creado exitosamente!',
+        'update_success' => '¡Documento actualizado exitosamente!',
+        'delete_success' => '¡Documento eliminado exitosamente!',
+        'delete_confirm' => '¿Está seguro de que desea eliminar este documento?',
+        'linked_references' => 'Referencias vinculadas',
+        'title_label' => 'Título',
+        'title_placeholder' => 'Título del documento (ej: Laravel/Livewire/Components)',
+        'title_hint' => 'Consejo: Use barras (/) en el título para organizar documentos en carpetas automáticamente',
+        'content_label' => 'Contenido',
+        'content_placeholder' => 'Escriba su markdown aquí...',
+        'saving' => 'Guardando...',
+    ],
+
+    // Quick Switcher
+    'quick_switcher' => [
+        'title' => 'Cambio rápido',
+        'placeholder' => 'Buscar documentos...',
+        'no_results' => 'No se encontraron documentos',
+        'navigate' => 'para navegar',
+        'select' => 'para seleccionar',
+        'close' => 'para cerrar',
+    ],
+
+    // Admin
+    'admin' => [
+        'user_management' => 'Gestión de usuarios',
+        'new_user' => 'Nuevo usuario',
+        'edit_user' => 'Editar usuario',
+        'create_user' => 'Crear usuario',
+        'users' => 'Usuarios',
+        'name' => 'Nombre',
+        'email' => 'Correo electrónico',
+        'password' => 'Contraseña',
+        'password_confirmation' => 'Confirmar contraseña',
+        'password_hint' => 'Deje en blanco para mantener la contraseña actual.',
+        'role' => 'Rol',
+        'admin' => 'Administrador',
+        'user' => 'Usuario',
+        'grant_admin' => 'Otorgar privilegios de administrador',
+        'created_at' => 'Fecha de creación',
+        'actions' => 'Acciones',
+        'edit' => 'Editar',
+        'delete' => 'Eliminar',
+        'no_users' => 'No se encontraron usuarios.',
+        'create_success' => 'Usuario creado exitosamente.',
+        'update_success' => 'Usuario actualizado exitosamente.',
+        'delete_success' => 'Usuario eliminado exitosamente.',
+        'cannot_delete_self' => 'No puede eliminarse a sí mismo.',
+        'self_admin_warning' => 'Eliminar sus propios privilegios de administrador le impedirá acceder al panel de administración.',
+    ],
+
+    // Settings
+    'settings' => [
+        'language' => 'Idioma',
+        'select_language' => 'Seleccionar idioma',
+        'language_updated' => 'Idioma actualizado exitosamente.',
+    ],
+
+    // Common
+    'common' => [
+        'save' => 'Guardar',
+        'cancel' => 'Cancelar',
+        'delete' => 'Eliminar',
+        'edit' => 'Editar',
+        'create' => 'Crear',
+        'update' => 'Actualizar',
+        'back' => 'Volver',
+        'confirm' => 'Confirmar',
+        'yes' => 'Sí',
+        'no' => 'No',
+        'loading' => 'Cargando...',
+        'error' => 'Error',
+        'success' => 'Éxito',
+    ],
+
+    // Auth
+    'auth' => [
+        'login' => 'Iniciar sesión',
+        'register' => 'Registrarse',
+        'email' => 'Correo electrónico',
+        'password' => 'Contraseña',
+        'remember_me' => 'Recordarme',
+        'forgot_password' => '¿Olvidó su contraseña?',
+        'confirm_password' => 'Confirmar contraseña',
+        'already_registered' => '¿Ya está registrado?',
+    ],
+];
+

src/lang/fr/messages.php

@@ -0,0 +1,117 @@
+<?php
+
+return [
+    // Navigation
+    'nav' => [
+        'dashboard' => 'Tableau de bord',
+        'knowledge_base' => 'Base de connaissances',
+        'profile' => 'Profil',
+        'user_management' => 'Gestion des utilisateurs',
+        'logout' => 'Déconnexion',
+        'login' => 'Connexion',
+        'register' => "S'inscrire",
+    ],
+
+    // Documents
+    'documents' => [
+        'title' => 'Documents',
+        'new_document' => 'Nouveau document',
+        'edit_document' => 'Modifier le document',
+        'edit' => 'Modifier',
+        'delete' => 'Supprimer',
+        'save' => 'Enregistrer',
+        'cancel' => 'Annuler',
+        'created_by' => 'Créé par',
+        'updated' => 'Mis à jour',
+        'path' => 'Chemin',
+        'last_modified' => 'Dernière modification',
+        'no_documents' => 'Aucun document trouvé',
+        'search_placeholder' => 'Rechercher des documents...',
+        'create_success' => 'Document créé avec succès !',
+        'update_success' => 'Document mis à jour avec succès !',
+        'delete_success' => 'Document supprimé avec succès !',
+        'delete_confirm' => 'Êtes-vous sûr de vouloir supprimer ce document ?',
+        'linked_references' => 'Références liées',
+        'title_label' => 'Titre',
+        'title_placeholder' => 'Titre du document (ex: Laravel/Livewire/Components)',
+        'title_hint' => 'Astuce: Utilisez des barres obliques (/) dans le titre pour organiser automatiquement les documents en dossiers',
+        'content_label' => 'Contenu',
+        'content_placeholder' => 'Écrivez votre markdown ici...',
+        'saving' => 'Enregistrement...',
+    ],
+
+    // Quick Switcher
+    'quick_switcher' => [
+        'title' => 'Changement rapide',
+        'placeholder' => 'Rechercher des documents...',
+        'no_results' => 'Aucun document trouvé',
+        'navigate' => 'pour naviguer',
+        'select' => 'pour sélectionner',
+        'close' => 'pour fermer',
+    ],
+
+    // Admin
+    'admin' => [
+        'user_management' => 'Gestion des utilisateurs',
+        'new_user' => 'Nouvel utilisateur',
+        'edit_user' => "Modifier l'utilisateur",
+        'create_user' => 'Créer un utilisateur',
+        'users' => 'Utilisateurs',
+        'name' => 'Nom',
+        'email' => 'E-mail',
+        'password' => 'Mot de passe',
+        'password_confirmation' => 'Confirmer le mot de passe',
+        'password_hint' => 'Laissez vide pour conserver le mot de passe actuel.',
+        'role' => 'Rôle',
+        'admin' => 'Administrateur',
+        'user' => 'Utilisateur',
+        'grant_admin' => "Accorder les privilèges d'administrateur",
+        'created_at' => 'Créé le',
+        'actions' => 'Actions',
+        'edit' => 'Modifier',
+        'delete' => 'Supprimer',
+        'no_users' => 'Aucun utilisateur trouvé.',
+        'create_success' => 'Utilisateur créé avec succès.',
+        'update_success' => 'Utilisateur mis à jour avec succès.',
+        'delete_success' => 'Utilisateur supprimé avec succès.',
+        'cannot_delete_self' => 'Vous ne pouvez pas vous supprimer vous-même.',
+        'self_admin_warning' => "Supprimer vos propres privilèges d'administrateur vous empêchera d'accéder au panneau d'administration.",
+    ],
+
+    // Settings
+    'settings' => [
+        'language' => 'Langue',
+        'select_language' => 'Sélectionner la langue',
+        'language_updated' => 'Langue mise à jour avec succès.',
+    ],
+
+    // Common
+    'common' => [
+        'save' => 'Enregistrer',
+        'cancel' => 'Annuler',
+        'delete' => 'Supprimer',
+        'edit' => 'Modifier',
+        'create' => 'Créer',
+        'update' => 'Mettre à jour',
+        'back' => 'Retour',
+        'confirm' => 'Confirmer',
+        'yes' => 'Oui',
+        'no' => 'Non',
+        'loading' => 'Chargement...',
+        'error' => 'Erreur',
+        'success' => 'Succès',
+    ],
+
+    // Auth
+    'auth' => [
+        'login' => 'Connexion',
+        'register' => "S'inscrire",
+        'email' => 'E-mail',
+        'password' => 'Mot de passe',
+        'remember_me' => 'Se souvenir de moi',
+        'forgot_password' => 'Mot de passe oublié ?',
+        'confirm_password' => 'Confirmer le mot de passe',
+        'already_registered' => 'Déjà inscrit ?',
+    ],
+];
+

src/lang/ja/messages.php

@@ -0,0 +1,117 @@
+<?php
+
+return [
+    // Navigation
+    'nav' => [
+        'dashboard' => 'ダッシュボード',
+        'knowledge_base' => 'ナレッジベース',
+        'profile' => 'プロフィール',
+        'user_management' => 'ユーザー管理',
+        'logout' => 'ログアウト',
+        'login' => 'ログイン',
+        'register' => '登録',
+    ],
+
+    // Documents
+    'documents' => [
+        'title' => 'ドキュメント',
+        'new_document' => '新規ドキュメント',
+        'edit_document' => 'ドキュメント編集',
+        'edit' => '編集',
+        'delete' => '削除',
+        'save' => '保存',
+        'cancel' => 'キャンセル',
+        'created_by' => '作成者',
+        'updated' => '更新日',
+        'path' => 'パス',
+        'last_modified' => '最終更新',
+        'no_documents' => 'ドキュメントが見つかりません',
+        'search_placeholder' => 'ドキュメントを検索...',
+        'create_success' => 'ドキュメントを作成しました！',
+        'update_success' => 'ドキュメントを更新しました！',
+        'delete_success' => 'ドキュメントを削除しました！',
+        'delete_confirm' => 'このドキュメントを削除してもよろしいですか？',
+        'linked_references' => 'リンク元',
+        'title_label' => 'タイトル',
+        'title_placeholder' => 'ドキュメントタイトル（例: Laravel/Livewire/Components）',
+        'title_hint' => 'ヒント: タイトルにスラッシュ(/)を含めると自動的にフォルダ構造が作成されます',
+        'content_label' => '本文',
+        'content_placeholder' => 'Markdownで記述してください...',
+        'saving' => '保存中...',
+    ],
+
+    // Quick Switcher
+    'quick_switcher' => [
+        'title' => 'クイックスイッチ',
+        'placeholder' => 'ドキュメントを検索...',
+        'no_results' => 'ドキュメントが見つかりません',
+        'navigate' => 'で移動',
+        'select' => 'で選択',
+        'close' => 'で閉じる',
+    ],
+
+    // Admin
+    'admin' => [
+        'user_management' => 'ユーザー管理',
+        'new_user' => '新規ユーザー',
+        'edit_user' => 'ユーザー編集',
+        'create_user' => 'ユーザー作成',
+        'users' => 'ユーザー',
+        'name' => '名前',
+        'email' => 'メールアドレス',
+        'password' => 'パスワード',
+        'password_confirmation' => 'パスワード（確認）',
+        'password_hint' => '変更しない場合は空欄のままにしてください。',
+        'role' => '権限',
+        'admin' => '管理者',
+        'user' => '一般ユーザー',
+        'grant_admin' => '管理者権限を付与する',
+        'created_at' => '登録日',
+        'actions' => '操作',
+        'edit' => '編集',
+        'delete' => '削除',
+        'no_users' => 'ユーザーが登録されていません。',
+        'create_success' => 'ユーザーを作成しました。',
+        'update_success' => 'ユーザー情報を更新しました。',
+        'delete_success' => 'ユーザーを削除しました。',
+        'cannot_delete_self' => '自分自身を削除することはできません。',
+        'self_admin_warning' => '自分自身の管理者権限を外すと、管理画面にアクセスできなくなります。',
+    ],
+
+    // Settings
+    'settings' => [
+        'language' => '言語',
+        'select_language' => '言語を選択',
+        'language_updated' => '言語を変更しました。',
+    ],
+
+    // Common
+    'common' => [
+        'save' => '保存',
+        'cancel' => 'キャンセル',
+        'delete' => '削除',
+        'edit' => '編集',
+        'create' => '作成',
+        'update' => '更新',
+        'back' => '戻る',
+        'confirm' => '確認',
+        'yes' => 'はい',
+        'no' => 'いいえ',
+        'loading' => '読み込み中...',
+        'error' => 'エラー',
+        'success' => '成功',
+    ],
+
+    // Auth
+    'auth' => [
+        'login' => 'ログイン',
+        'register' => '登録',
+        'email' => 'メールアドレス',
+        'password' => 'パスワード',
+        'remember_me' => 'ログイン状態を保持',
+        'forgot_password' => 'パスワードをお忘れですか？',
+        'confirm_password' => 'パスワード（確認）',
+        'already_registered' => '既にアカウントをお持ちですか？',
+    ],
+];
+

src/lang/ko/messages.php

@@ -0,0 +1,117 @@
+<?php
+
+return [
+    // Navigation
+    'nav' => [
+        'dashboard' => '대시보드',
+        'knowledge_base' => '지식 베이스',
+        'profile' => '프로필',
+        'user_management' => '사용자 관리',
+        'logout' => '로그아웃',
+        'login' => '로그인',
+        'register' => '회원가입',
+    ],
+
+    // Documents
+    'documents' => [
+        'title' => '문서',
+        'new_document' => '새 문서',
+        'edit_document' => '문서 편집',
+        'edit' => '편집',
+        'delete' => '삭제',
+        'save' => '저장',
+        'cancel' => '취소',
+        'created_by' => '작성자',
+        'updated' => '업데이트',
+        'path' => '경로',
+        'last_modified' => '마지막 수정',
+        'no_documents' => '문서를 찾을 수 없습니다',
+        'search_placeholder' => '문서 검색...',
+        'create_success' => '문서가 성공적으로 생성되었습니다!',
+        'update_success' => '문서가 성공적으로 업데이트되었습니다!',
+        'delete_success' => '문서가 성공적으로 삭제되었습니다!',
+        'delete_confirm' => '이 문서를 삭제하시겠습니까?',
+        'linked_references' => '연결된 참조',
+        'title_label' => '제목',
+        'title_placeholder' => '문서 제목 (예: Laravel/Livewire/Components)',
+        'title_hint' => '팁: 제목에 슬래시(/)를 사용하면 문서를 폴더로 자동 정리할 수 있습니다',
+        'content_label' => '내용',
+        'content_placeholder' => '여기에 마크다운을 작성하세요...',
+        'saving' => '저장 중...',
+    ],
+
+    // Quick Switcher
+    'quick_switcher' => [
+        'title' => '빠른 전환',
+        'placeholder' => '문서 검색...',
+        'no_results' => '문서를 찾을 수 없습니다',
+        'navigate' => '탐색',
+        'select' => '선택',
+        'close' => '닫기',
+    ],
+
+    // Admin
+    'admin' => [
+        'user_management' => '사용자 관리',
+        'new_user' => '새 사용자',
+        'edit_user' => '사용자 편집',
+        'create_user' => '사용자 생성',
+        'users' => '사용자',
+        'name' => '이름',
+        'email' => '이메일',
+        'password' => '비밀번호',
+        'password_confirmation' => '비밀번호 확인',
+        'password_hint' => '현재 비밀번호를 유지하려면 비워두세요.',
+        'role' => '역할',
+        'admin' => '관리자',
+        'user' => '일반 사용자',
+        'grant_admin' => '관리자 권한 부여',
+        'created_at' => '생성일',
+        'actions' => '작업',
+        'edit' => '편집',
+        'delete' => '삭제',
+        'no_users' => '사용자를 찾을 수 없습니다.',
+        'create_success' => '사용자가 성공적으로 생성되었습니다.',
+        'update_success' => '사용자가 성공적으로 업데이트되었습니다.',
+        'delete_success' => '사용자가 성공적으로 삭제되었습니다.',
+        'cannot_delete_self' => '자신을 삭제할 수 없습니다.',
+        'self_admin_warning' => '자신의 관리자 권한을 제거하면 관리 패널에 액세스할 수 없게 됩니다.',
+    ],
+
+    // Settings
+    'settings' => [
+        'language' => '언어',
+        'select_language' => '언어 선택',
+        'language_updated' => '언어가 성공적으로 업데이트되었습니다.',
+    ],
+
+    // Common
+    'common' => [
+        'save' => '저장',
+        'cancel' => '취소',
+        'delete' => '삭제',
+        'edit' => '편집',
+        'create' => '생성',
+        'update' => '업데이트',
+        'back' => '뒤로',
+        'confirm' => '확인',
+        'yes' => '예',
+        'no' => '아니오',
+        'loading' => '로딩 중...',
+        'error' => '오류',
+        'success' => '성공',
+    ],
+
+    // Auth
+    'auth' => [
+        'login' => '로그인',
+        'register' => '회원가입',
+        'email' => '이메일',
+        'password' => '비밀번호',
+        'remember_me' => '로그인 상태 유지',
+        'forgot_password' => '비밀번호를 잊으셨나요?',
+        'confirm_password' => '비밀번호 확인',
+        'already_registered' => '이미 계정이 있으신가요?',
+    ],
+];
+

src/lang/zh-CN/messages.php

@@ -0,0 +1,117 @@
+<?php
+
+return [
+    // Navigation
+    'nav' => [
+        'dashboard' => '仪表盘',
+        'knowledge_base' => '知识库',
+        'profile' => '个人资料',
+        'user_management' => '用户管理',
+        'logout' => '退出登录',
+        'login' => '登录',
+        'register' => '注册',
+    ],
+
+    // Documents
+    'documents' => [
+        'title' => '文档',
+        'new_document' => '新建文档',
+        'edit_document' => '编辑文档',
+        'edit' => '编辑',
+        'delete' => '删除',
+        'save' => '保存',
+        'cancel' => '取消',
+        'created_by' => '创建者',
+        'updated' => '更新时间',
+        'path' => '路径',
+        'last_modified' => '最后修改',
+        'no_documents' => '未找到文档',
+        'search_placeholder' => '搜索文档...',
+        'create_success' => '文档创建成功！',
+        'update_success' => '文档更新成功！',
+        'delete_success' => '文档删除成功！',
+        'delete_confirm' => '确定要删除此文档吗？',
+        'linked_references' => '链接引用',
+        'title_label' => '标题',
+        'title_placeholder' => '文档标题（例如：Laravel/Livewire/Components）',
+        'title_hint' => '提示：在标题中使用斜杠（/）可自动将文档组织到文件夹中',
+        'content_label' => '内容',
+        'content_placeholder' => '在此输入Markdown内容...',
+        'saving' => '保存中...',
+    ],
+
+    // Quick Switcher
+    'quick_switcher' => [
+        'title' => '快速切换',
+        'placeholder' => '搜索文档...',
+        'no_results' => '未找到文档',
+        'navigate' => '导航',
+        'select' => '选择',
+        'close' => '关闭',
+    ],
+
+    // Admin
+    'admin' => [
+        'user_management' => '用户管理',
+        'new_user' => '新建用户',
+        'edit_user' => '编辑用户',
+        'create_user' => '创建用户',
+        'users' => '用户',
+        'name' => '姓名',
+        'email' => '邮箱',
+        'password' => '密码',
+        'password_confirmation' => '确认密码',
+        'password_hint' => '留空以保持当前密码。',
+        'role' => '角色',
+        'admin' => '管理员',
+        'user' => '普通用户',
+        'grant_admin' => '授予管理员权限',
+        'created_at' => '创建日期',
+        'actions' => '操作',
+        'edit' => '编辑',
+        'delete' => '删除',
+        'no_users' => '未找到用户。',
+        'create_success' => '用户创建成功。',
+        'update_success' => '用户更新成功。',
+        'delete_success' => '用户删除成功。',
+        'cannot_delete_self' => '您不能删除自己。',
+        'self_admin_warning' => '移除您自己的管理员权限将使您无法访问管理面板。',
+    ],
+
+    // Settings
+    'settings' => [
+        'language' => '语言',
+        'select_language' => '选择语言',
+        'language_updated' => '语言更新成功。',
+    ],
+
+    // Common
+    'common' => [
+        'save' => '保存',
+        'cancel' => '取消',
+        'delete' => '删除',
+        'edit' => '编辑',
+        'create' => '创建',
+        'update' => '更新',
+        'back' => '返回',
+        'confirm' => '确认',
+        'yes' => '是',
+        'no' => '否',
+        'loading' => '加载中...',
+        'error' => '错误',
+        'success' => '成功',
+    ],
+
+    // Auth
+    'auth' => [
+        'login' => '登录',
+        'register' => '注册',
+        'email' => '邮箱',
+        'password' => '密码',
+        'remember_me' => '记住我',
+        'forgot_password' => '忘记密码？',
+        'confirm_password' => '确认密码',
+        'already_registered' => '已有账号？',
+    ],
+];
+

src/lang/zh-TW/messages.php

@@ -0,0 +1,117 @@
+<?php
+
+return [
+    // Navigation
+    'nav' => [
+        'dashboard' => '儀表板',
+        'knowledge_base' => '知識庫',
+        'profile' => '個人資料',
+        'user_management' => '使用者管理',
+        'logout' => '登出',
+        'login' => '登入',
+        'register' => '註冊',
+    ],
+
+    // Documents
+    'documents' => [
+        'title' => '文件',
+        'new_document' => '新增文件',
+        'edit_document' => '編輯文件',
+        'edit' => '編輯',
+        'delete' => '刪除',
+        'save' => '儲存',
+        'cancel' => '取消',
+        'created_by' => '建立者',
+        'updated' => '更新時間',
+        'path' => '路徑',
+        'last_modified' => '最後修改',
+        'no_documents' => '找不到文件',
+        'search_placeholder' => '搜尋文件...',
+        'create_success' => '文件建立成功！',
+        'update_success' => '文件更新成功！',
+        'delete_success' => '文件刪除成功！',
+        'delete_confirm' => '確定要刪除此文件嗎？',
+        'linked_references' => '連結參照',
+        'title_label' => '標題',
+        'title_placeholder' => '文件標題（例如：Laravel/Livewire/Components）',
+        'title_hint' => '提示：在標題中使用斜線（/）可自動將文件組織到資料夾中',
+        'content_label' => '內容',
+        'content_placeholder' => '在此輸入Markdown內容...',
+        'saving' => '儲存中...',
+    ],
+
+    // Quick Switcher
+    'quick_switcher' => [
+        'title' => '快速切換',
+        'placeholder' => '搜尋文件...',
+        'no_results' => '找不到文件',
+        'navigate' => '導覽',
+        'select' => '選擇',
+        'close' => '關閉',
+    ],
+
+    // Admin
+    'admin' => [
+        'user_management' => '使用者管理',
+        'new_user' => '新增使用者',
+        'edit_user' => '編輯使用者',
+        'create_user' => '建立使用者',
+        'users' => '使用者',
+        'name' => '姓名',
+        'email' => '電子郵件',
+        'password' => '密碼',
+        'password_confirmation' => '確認密碼',
+        'password_hint' => '留空以保持目前密碼。',
+        'role' => '角色',
+        'admin' => '管理員',
+        'user' => '一般使用者',
+        'grant_admin' => '授予管理員權限',
+        'created_at' => '建立日期',
+        'actions' => '操作',
+        'edit' => '編輯',
+        'delete' => '刪除',
+        'no_users' => '找不到使用者。',
+        'create_success' => '使用者建立成功。',
+        'update_success' => '使用者更新成功。',
+        'delete_success' => '使用者刪除成功。',
+        'cannot_delete_self' => '您無法刪除自己。',
+        'self_admin_warning' => '移除您自己的管理員權限將使您無法存取管理面板。',
+    ],
+
+    // Settings
+    'settings' => [
+        'language' => '語言',
+        'select_language' => '選擇語言',
+        'language_updated' => '語言更新成功。',
+    ],
+
+    // Common
+    'common' => [
+        'save' => '儲存',
+        'cancel' => '取消',
+        'delete' => '刪除',
+        'edit' => '編輯',
+        'create' => '建立',
+        'update' => '更新',
+        'back' => '返回',
+        'confirm' => '確認',
+        'yes' => '是',
+        'no' => '否',
+        'loading' => '載入中...',
+        'error' => '錯誤',
+        'success' => '成功',
+    ],
+
+    // Auth
+    'auth' => [
+        'login' => '登入',
+        'register' => '註冊',
+        'email' => '電子郵件',
+        'password' => '密碼',
+        'remember_me' => '記住我',
+        'forgot_password' => '忘記密碼？',
+        'confirm_password' => '確認密碼',
+        'already_registered' => '已有帳號？',
+    ],
+];
+

src/resources/views/admin/users/create.blade.php

@@ -7,7 +7,7 @@
                 </svg>
             </a>
             <h2 class="font-semibold text-xl text-gray-800 leading-tight">
-                新規ユーザー作成
+                {{ __('messages.admin.create_user') }}
             </h2>
         </div>
     </x-slot>
@@ -21,28 +21,28 @@
 
                         <!-- Name -->
                         <div>
-                            <x-input-label for="name" value="名前" />
+                            <x-input-label for="name" :value="__('messages.admin.name')" />
                             <x-text-input id="name" class="block mt-1 w-full" type="text" name="name" :value="old('name')" required autofocus autocomplete="name" />
                             <x-input-error :messages="$errors->get('name')" class="mt-2" />
                         </div>
 
                         <!-- Email Address -->
                         <div class="mt-4">
-                            <x-input-label for="email" value="メールアドレス" />
+                            <x-input-label for="email" :value="__('messages.admin.email')" />
                             <x-text-input id="email" class="block mt-1 w-full" type="email" name="email" :value="old('email')" required autocomplete="username" />
                             <x-input-error :messages="$errors->get('email')" class="mt-2" />
                         </div>
 
                         <!-- Password -->
                         <div class="mt-4">
-                            <x-input-label for="password" value="パスワード" />
+                            <x-input-label for="password" :value="__('messages.admin.password')" />
                             <x-text-input id="password" class="block mt-1 w-full" type="password" name="password" required autocomplete="new-password" />
                             <x-input-error :messages="$errors->get('password')" class="mt-2" />
                         </div>
 
                         <!-- Confirm Password -->
                         <div class="mt-4">
-                            <x-input-label for="password_confirmation" value="パスワード（確認）" />
+                            <x-input-label for="password_confirmation" :value="__('messages.admin.password_confirmation')" />
                             <x-text-input id="password_confirmation" class="block mt-1 w-full" type="password" name="password_confirmation" required autocomplete="new-password" />
                             <x-input-error :messages="$errors->get('password_confirmation')" class="mt-2" />
                         </div>
@@ -51,16 +51,16 @@
                         <div class="mt-4">
                             <label for="is_admin" class="inline-flex items-center">
                                 <input id="is_admin" type="checkbox" class="rounded border-gray-300 text-indigo-600 shadow-sm focus:ring-indigo-500" name="is_admin" value="1" {{ old('is_admin') ? 'checked' : '' }}>
-                                <span class="ml-2 text-sm text-gray-600">管理者権限を付与する</span>
+                                <span class="ml-2 text-sm text-gray-600">{{ __('messages.admin.grant_admin') }}</span>
                             </label>
                         </div>
 
                         <div class="flex items-center justify-end mt-6">
                             <a href="{{ route('admin.users.index') }}" class="text-sm text-gray-600 hover:text-gray-900 mr-4">
-                                キャンセル
+                                {{ __('messages.common.cancel') }}
                             </a>
                             <x-primary-button>
-                                作成
+                                {{ __('messages.common.create') }}
                             </x-primary-button>
                         </div>
                     </form>
@@ -69,4 +69,3 @@
         </div>
     </div>
 </x-app-layout>
-

src/resources/views/admin/users/edit.blade.php

@@ -7,7 +7,7 @@
                 </svg>
             </a>
             <h2 class="font-semibold text-xl text-gray-800 leading-tight">
-                ユーザー編集: {{ $user->name }}
+                {{ __('messages.admin.edit_user') }}: {{ $user->name }}
             </h2>
         </div>
     </x-slot>
@@ -22,29 +22,29 @@
 
                         <!-- Name -->
                         <div>
-                            <x-input-label for="name" value="名前" />
+                            <x-input-label for="name" :value="__('messages.admin.name')" />
                             <x-text-input id="name" class="block mt-1 w-full" type="text" name="name" :value="old('name', $user->name)" required autofocus autocomplete="name" />
                             <x-input-error :messages="$errors->get('name')" class="mt-2" />
                         </div>
 
                         <!-- Email Address -->
                         <div class="mt-4">
-                            <x-input-label for="email" value="メールアドレス" />
+                            <x-input-label for="email" :value="__('messages.admin.email')" />
                             <x-text-input id="email" class="block mt-1 w-full" type="email" name="email" :value="old('email', $user->email)" required autocomplete="username" />
                             <x-input-error :messages="$errors->get('email')" class="mt-2" />
                         </div>
 
                         <!-- Password -->
                         <div class="mt-4">
-                            <x-input-label for="password" value="パスワード" />
+                            <x-input-label for="password" :value="__('messages.admin.password')" />
-                            <x-text-input id="password" class="block mt-1 w-full" type="password" name="password" autocomplete="new-password" placeholder="変更する場合のみ入力" />
+                            <x-text-input id="password" class="block mt-1 w-full" type="password" name="password" autocomplete="new-password" />
                             <x-input-error :messages="$errors->get('password')" class="mt-2" />
-                            <p class="mt-1 text-sm text-gray-500">変更しない場合は空欄のままにしてください。</p>
+                            <p class="mt-1 text-sm text-gray-500">{{ __('messages.admin.password_hint') }}</p>
                         </div>
 
                         <!-- Confirm Password -->
                         <div class="mt-4">
-                            <x-input-label for="password_confirmation" value="パスワード（確認）" />
+                            <x-input-label for="password_confirmation" :value="__('messages.admin.password_confirmation')" />
                             <x-text-input id="password_confirmation" class="block mt-1 w-full" type="password" name="password_confirmation" autocomplete="new-password" />
                             <x-input-error :messages="$errors->get('password_confirmation')" class="mt-2" />
                         </div>
@@ -53,19 +53,19 @@
                         <div class="mt-4">
                             <label for="is_admin" class="inline-flex items-center">
                                 <input id="is_admin" type="checkbox" class="rounded border-gray-300 text-indigo-600 shadow-sm focus:ring-indigo-500" name="is_admin" value="1" {{ old('is_admin', $user->is_admin) ? 'checked' : '' }}>
-                                <span class="ml-2 text-sm text-gray-600">管理者権限を付与する</span>
+                                <span class="ml-2 text-sm text-gray-600">{{ __('messages.admin.grant_admin') }}</span>
                             </label>
                             @if($user->id === auth()->id())
-                                <p class="mt-1 text-sm text-yellow-600">※自分自身の管理者権限を外すと、管理画面にアクセスできなくなります。</p>
+                                <p class="mt-1 text-sm text-yellow-600">※{{ __('messages.admin.self_admin_warning') }}</p>
                             @endif
                         </div>
 
                         <div class="flex items-center justify-end mt-6">
                             <a href="{{ route('admin.users.index') }}" class="text-sm text-gray-600 hover:text-gray-900 mr-4">
-                                キャンセル
+                                {{ __('messages.common.cancel') }}
                             </a>
                             <x-primary-button>
-                                更新
+                                {{ __('messages.common.update') }}
                             </x-primary-button>
                         </div>
                     </form>
@@ -74,4 +74,3 @@
         </div>
     </div>
 </x-app-layout>
-

src/resources/views/admin/users/index.blade.php

@@ -2,13 +2,13 @@
     <x-slot name="header">
         <div class="flex justify-between items-center">
             <h2 class="font-semibold text-xl text-gray-800 leading-tight">
-                ユーザー管理
+                {{ __('messages.admin.user_management') }}
             </h2>
             <a href="{{ route('admin.users.create') }}" class="inline-flex items-center px-4 py-2 bg-indigo-600 border border-transparent rounded-md font-semibold text-xs text-white uppercase tracking-widest hover:bg-indigo-700 focus:bg-indigo-700 active:bg-indigo-900 focus:outline-none focus:ring-2 focus:ring-indigo-500 focus:ring-offset-2 transition ease-in-out duration-150">
                 <svg class="w-4 h-4 mr-2" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                     <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 4v16m8-8H4"></path>
                 </svg>
-                新規ユーザー
+                {{ __('messages.admin.new_user') }}
             </a>
         </div>
     </x-slot>
@@ -36,19 +36,19 @@
                                     ID
                                 </th>
                                 <th scope="col" class="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
-                                    名前
+                                    {{ __('messages.admin.name') }}
                                 </th>
                                 <th scope="col" class="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
-                                    メールアドレス
+                                    {{ __('messages.admin.email') }}
                                 </th>
                                 <th scope="col" class="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
-                                    権限
+                                    {{ __('messages.admin.role') }}
                                 </th>
                                 <th scope="col" class="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider">
-                                    登録日
+                                    {{ __('messages.admin.created_at') }}
                                 </th>
                                 <th scope="col" class="relative px-6 py-3">
-                                    <span class="sr-only">操作</span>
+                                    <span class="sr-only">{{ __('messages.admin.actions') }}</span>
                                 </th>
                             </tr>
                         </thead>
@@ -78,11 +78,11 @@
                                     <td class="px-6 py-4 whitespace-nowrap">
                                         @if($user->is_admin)
                                             <span class="px-2 inline-flex text-xs leading-5 font-semibold rounded-full bg-indigo-100 text-indigo-800">
-                                                管理者
+                                                {{ __('messages.admin.admin') }}
                                             </span>
                                         @else
                                             <span class="px-2 inline-flex text-xs leading-5 font-semibold rounded-full bg-gray-100 text-gray-800">
-                                                一般ユーザー
+                                                {{ __('messages.admin.user') }}
                                             </span>
                                         @endif
                                     </td>
@@ -90,12 +90,12 @@
                                         {{ $user->created_at->format('Y/m/d H:i') }}
                                     </td>
                                     <td class="px-6 py-4 whitespace-nowrap text-right text-sm font-medium">
-                                        <a href="{{ route('admin.users.edit', $user) }}" class="text-indigo-600 hover:text-indigo-900 mr-3">編集</a>
+                                        <a href="{{ route('admin.users.edit', $user) }}" class="text-indigo-600 hover:text-indigo-900 mr-3">{{ __('messages.admin.edit') }}</a>
                                         @if($user->id !== auth()->id())
-                                            <form action="{{ route('admin.users.destroy', $user) }}" method="POST" class="inline" onsubmit="return confirm('本当に削除しますか？')">
+                                            <form action="{{ route('admin.users.destroy', $user) }}" method="POST" class="inline" onsubmit="return confirm('{{ __('messages.documents.delete_confirm') }}')">
                                                 @csrf
                                                 @method('DELETE')
-                                                <button type="submit" class="text-red-600 hover:text-red-900">削除</button>
+                                                <button type="submit" class="text-red-600 hover:text-red-900">{{ __('messages.admin.delete') }}</button>
                                             </form>
                                         @endif
                                     </td>
@@ -103,7 +103,7 @@
                             @empty
                                 <tr>
                                     <td colspan="6" class="px-6 py-4 text-center text-sm text-gray-500">
-                                        ユーザーが登録されていません。
+                                        {{ __('messages.admin.no_users') }}
                                     </td>
                                 </tr>
                             @endforelse
@@ -118,4 +118,3 @@
         </div>
     </div>
 </x-app-layout>
-

src/resources/views/layouts/knowledge-base.blade.php

@@ -15,7 +15,7 @@
         <script>document.addEventListener('livewire:navigated', function() { hljs.highlightAll(); });</script>
         <style>
             pre code.hljs {
-                background: #1e1e1e !important; /* VSCode dark と同じ */
+                background: #1e1e1e !important;
                 color: #dcdcdc !important;
                 padding: 1rem;
                 border-radius: 8px;
@@ -50,7 +50,7 @@ class="inline-flex items-center px-3 py-2 border border-gray-300 shadow-sm text-
                                 <svg class="h-4 w-4 mr-2" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                                     <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M21 21l-6-6m2-5a7 7 0 11-14 0 7 7 0 0114 0z"></path>
                                 </svg>
-                                Quick Switch
+                                {{ __('messages.quick_switcher.title') }}
                                 <kbd class="ml-2 px-2 py-1 text-xs font-semibold text-gray-800 bg-gray-100 border border-gray-200 rounded">
                                     Ctrl+K
                                 </kbd>
@@ -75,7 +75,7 @@ class="flex items-center text-sm font-medium text-gray-700 hover:text-gray-900 f
                                         class="absolute right-0 mt-2 w-48 bg-white rounded-md shadow-lg py-1 ring-1 ring-black ring-opacity-5"
                                     >
                                         <a href="{{ route('profile.edit') }}" class="block px-4 py-2 text-sm text-gray-700 hover:bg-gray-100">
-                                            Profile
+                                            {{ __('messages.nav.profile') }}
                                         </a>
                                         @if(Auth::user()->isAdmin())
                                             <a href="{{ route('admin.users.index') }}" class="block px-4 py-2 text-sm text-gray-700 hover:bg-gray-100">
@@ -83,21 +83,21 @@ class="absolute right-0 mt-2 w-48 bg-white rounded-md shadow-lg py-1 ring-1 ring
                                                     <svg class="w-4 h-4 mr-2" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                                                         <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 4.354a4 4 0 110 5.292M15 21H3v-1a6 6 0 0112 0v1zm0 0h6v-1a6 6 0 00-9-5.197M13 7a4 4 0 11-8 0 4 4 0 018 0z"></path>
                                                     </svg>
-                                                    ユーザー管理
+                                                    {{ __('messages.nav.user_management') }}
                                                 </span>
                                             </a>
                                         @endif
                                         <form method="POST" action="{{ route('logout') }}">
                                             @csrf
                                             <button type="submit" class="w-full text-left block px-4 py-2 text-sm text-gray-700 hover:bg-gray-100">
-                                                Logout
+                                                {{ __('messages.nav.logout') }}
                                             </button>
                                         </form>
                                     </div>
                                 </div>
                             @else
                                 <a href="{{ route('login') }}" class="text-sm text-gray-700 hover:text-gray-900">
-                                    Login
+                                    {{ __('messages.nav.login') }}
                                 </a>
                             @endauth
                         </div>
@@ -127,20 +127,17 @@ class="absolute right-0 mt-2 w-48 bg-white rounded-md shadow-lg py-1 ring-1 ring
         <!-- Global Keyboard Shortcuts -->
         <script>
             document.addEventListener('keydown', function(e) {
-                // Ctrl+K or Cmd+K for quick switcher
                 if ((e.ctrlKey || e.metaKey) && e.key === 'k') {
                     e.preventDefault();
                     window.dispatchEvent(new CustomEvent('open-quick-switcher'));
                 }
             });
 
-            // Sidebar folder state management
             document.addEventListener('alpine:init', () => {
                 Alpine.data('sidebarState', () => ({
                     expandedFolders: [],
 
                     initExpandedFolders() {
-                        // Load from localStorage
                         const stored = localStorage.getItem('kb_expanded_folders');
                         if (stored) {
                             try {
@@ -158,7 +155,6 @@ class="absolute right-0 mt-2 w-48 bg-white rounded-md shadow-lg py-1 ring-1 ring
                         } else {
                             this.expandedFolders.push(path);
                         }
-                        // Save to localStorage
                         localStorage.setItem('kb_expanded_folders', JSON.stringify(this.expandedFolders));
                     },
 

src/resources/views/layouts/navigation.blade.php

@@ -13,13 +13,13 @@
                 <!-- Navigation Links -->
                 <div class="hidden space-x-8 sm:-my-px sm:ms-10 sm:flex">
                     <x-nav-link :href="route('dashboard')" :active="request()->routeIs('dashboard')">
-                        {{ __('Dashboard') }}
+                        {{ __('messages.nav.dashboard') }}
                     </x-nav-link>
                     <x-nav-link href="/" :active="false">
                         <svg class="w-4 h-4 mr-1 inline" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                             <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 6.042A8.967 8.967 0 006 3.75c-1.052 0-2.062.18-3 .512v14.25A8.987 8.987 0 016 18c2.305 0 4.408.867 6 2.292m0-14.25a8.966 8.966 0 016-2.292c1.052 0 2.062.18 3 .512v14.25A8.987 8.987 0 0018 18a8.967 8.967 0 00-6 2.292m0-14.25v14.25"></path>
                         </svg>
-                        {{ __('Knowledge Base') }}
+                        {{ __('messages.nav.knowledge_base') }}
                     </x-nav-link>
                 </div>
             </div>
@@ -41,12 +41,12 @@
 
                     <x-slot name="content">
                         <x-dropdown-link :href="route('profile.edit')">
-                            {{ __('Profile') }}
+                            {{ __('messages.nav.profile') }}
                         </x-dropdown-link>
 
                         @if(Auth::user()->isAdmin())
                             <x-dropdown-link :href="route('admin.users.index')">
-                                {{ __('ユーザー管理') }}
+                                {{ __('messages.nav.user_management') }}
                             </x-dropdown-link>
                         @endif
 
@@ -57,7 +57,7 @@
                             <x-dropdown-link :href="route('logout')"
                                     onclick="event.preventDefault();
                                                 this.closest('form').submit();">
-                                {{ __('Log Out') }}
+                                {{ __('messages.nav.logout') }}
                             </x-dropdown-link>
                         </form>
                     </x-slot>
@@ -80,10 +80,10 @@
     <div :class="{'block': open, 'hidden': ! open}" class="hidden sm:hidden">
         <div class="pt-2 pb-3 space-y-1">
             <x-responsive-nav-link :href="route('dashboard')" :active="request()->routeIs('dashboard')">
-                {{ __('Dashboard') }}
+                {{ __('messages.nav.dashboard') }}
             </x-responsive-nav-link>
             <x-responsive-nav-link href="/" :active="false">
-                {{ __('Knowledge Base') }}
+                {{ __('messages.nav.knowledge_base') }}
             </x-responsive-nav-link>
         </div>
 
@@ -96,12 +96,12 @@
 
             <div class="mt-3 space-y-1">
                 <x-responsive-nav-link :href="route('profile.edit')">
-                    {{ __('Profile') }}
+                    {{ __('messages.nav.profile') }}
                 </x-responsive-nav-link>
 
                 @if(Auth::user()->isAdmin())
                     <x-responsive-nav-link :href="route('admin.users.index')">
-                        {{ __('ユーザー管理') }}
+                        {{ __('messages.nav.user_management') }}
                     </x-responsive-nav-link>
                 @endif
 
@@ -112,7 +112,7 @@
                     <x-responsive-nav-link :href="route('logout')"
                             onclick="event.preventDefault();
                                         this.closest('form').submit();">
-                        {{ __('Log Out') }}
+                        {{ __('messages.nav.logout') }}
                     </x-responsive-nav-link>
                 </form>
             </div>

src/resources/views/livewire/document-editor.blade.php

@@ -15,7 +15,7 @@
     <!-- Header -->
     <div class="mb-6 flex items-center justify-between">
         <h1 class="text-3xl font-bold text-gray-900">
-            {{ $isEditMode ? 'Edit Document' : 'New Document' }}
+            {{ $isEditMode ? __('messages.documents.edit_document') : __('messages.documents.new_document') }}
         </h1>
 
         <div class="flex space-x-3">
@@ -24,22 +24,22 @@
                     href="{{ route('documents.show', $document) }}"
                     class="inline-flex items-center px-4 py-2 border border-gray-300 rounded-md text-sm font-medium text-gray-700 bg-white hover:bg-gray-50"
                 >
-                    Cancel
+                    {{ __('messages.common.cancel') }}
                 </a>
 
                 <button
                     wire:click="delete"
-                    wire:confirm="Are you sure you want to delete this document?"
+                    wire:confirm="{{ __('messages.documents.delete_confirm') }}"
                     class="inline-flex items-center px-4 py-2 border border-red-300 rounded-md text-sm font-medium text-red-700 bg-white hover:bg-red-50"
                 >
-                    Delete
+                    {{ __('messages.documents.delete') }}
                 </button>
             @else
                 <a
                     href="{{ route('documents.show', 'home') }}"
                     class="inline-flex items-center px-4 py-2 border border-gray-300 rounded-md text-sm font-medium text-gray-700 bg-white hover:bg-gray-50"
                 >
-                    Cancel
+                    {{ __('messages.common.cancel') }}
                 </a>
             @endif
 
@@ -50,7 +50,7 @@ class="inline-flex items-center px-4 py-2 bg-indigo-600 border border-transparen
                 <svg class="w-4 h-4 mr-2" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                     <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M8 7H5a2 2 0 00-2 2v9a2 2 0 002 2h14a2 2 0 002-2V9a2 2 0 00-2-2h-3m-1 4l-3 3m0 0l-3-3m3 3V4"></path>
                 </svg>
-                Save
+                {{ __('messages.documents.save') }}
             </button>
         </div>
     </div>
@@ -60,27 +60,27 @@ class="inline-flex items-center px-4 py-2 bg-indigo-600 border border-transparen
         <!-- Title -->
         <div>
             <label for="title" class="block text-sm font-medium text-gray-700 mb-2">
-                Title
+                {{ __('messages.documents.title_label') }}
             </label>
             <input
                 type="text"
                 id="title"
                 wire:model="title"
                 class="w-full px-4 py-2 border border-gray-300 rounded-md focus:ring-2 focus:ring-indigo-500 focus:border-indigo-500"
-                placeholder="Document Title (use / for folders, e.g. Laravel/Livewire/Components)"
+                placeholder="{{ __('messages.documents.title_placeholder') }}"
             >
             @error('title')
                 <p class="mt-1 text-sm text-red-600">{{ $message }}</p>
             @enderror
             <p class="mt-1 text-xs text-gray-500">
-                Tip: Use slashes (/) in the title to organize documents into folders automatically
+                {{ __('messages.documents.title_hint') }}
             </p>
         </div>
 
         <!-- Markdown Editor -->
         <div>
             <label class="block text-sm font-medium text-gray-700 mb-2">
-                Content
+                {{ __('messages.documents.content_label') }}
             </label>
             <div wire:ignore>
                 <div x-data="markdownEditor()" x-init="initEditor()">
@@ -103,12 +103,12 @@ class="w-full"
                     <circle class="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" stroke-width="4"></circle>
                     <path class="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"></path>
                 </svg>
-                Saving...
+                {{ __('messages.documents.saving') }}
             </div>
 
             @if($isEditMode && $document)
                 <div>
-                    Path: <code class="text-xs bg-gray-100 px-2 py-1 rounded">{{ $document->path }}</code>
+                    {{ __('messages.documents.path') }}: <code class="text-xs bg-gray-100 px-2 py-1 rounded">{{ $document->path }}</code>
                 </div>
             @endif
         </div>
@@ -137,7 +137,7 @@ class="w-full"
                         autosave: {
                             enabled: false,
                         },
-                        placeholder: 'Write your markdown here...',
+                        placeholder: '{{ __("messages.documents.content_placeholder") }}',
                         toolbar: [
                             'bold', 'italic', 'heading', '|',
                             'quote', 'unordered-list', 'ordered-list', '|',
@@ -148,9 +148,7 @@ class="w-full"
                         status: ['lines', 'words', 'cursor'],
                     });
 
-                    // エディタの変更をLivewireに反映
                     this.editor.codemirror.on('change', () => {
-                        // wire:ignoreの外にあるhidden inputを探す
                         const formElement = this.$el.closest('form');
                         const hiddenInput = formElement.querySelector('input[type="hidden"][wire\\:model="content"]');
                         if (hiddenInput) {

src/resources/views/livewire/document-viewer.blade.php

@@ -14,7 +14,7 @@ class="inline-flex items-center px-4 py-2 bg-indigo-600 text-white text-sm font-
                     <svg class="w-4 h-4 mr-2" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                         <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M11 5H6a2 2 0 00-2 2v11a2 2 0 002 2h11a2 2 0 002-2v-5m-1.414-9.414a2 2 0 112.828 2.828L11.828 15H9v-2.828l8.586-8.586z"></path>
                     </svg>
-                    Edit
+                    {{ __('messages.documents.edit') }}
                 </a>
             @endauth
         </div>
@@ -22,12 +22,12 @@ class="inline-flex items-center px-4 py-2 bg-indigo-600 text-white text-sm font-
         <div class="flex items-center text-sm text-gray-500 space-x-4">
             @if($document->created_by)
                 <span>
-                    Created by {{ $document->creator->name }}
+                    {{ __('messages.documents.created_by') }} {{ $document->creator->name }}
                 </span>
             @endif
 
             <span>
-                Updated {{ $document->updated_at->diffForHumans() }}
+                {{ __('messages.documents.updated') }} {{ $document->updated_at->diffForHumans() }}
             </span>
         </div>
     </div>
@@ -41,7 +41,7 @@ class="inline-flex items-center px-4 py-2 bg-indigo-600 text-white text-sm font-
     @if(count($backlinks) > 0)
         <div class="border-t border-gray-200 pt-8">
             <h2 class="text-xl font-semibold text-gray-900 mb-4">
-                Linked References
+                {{ __('messages.documents.linked_references') }}
             </h2>
 
             <div class="space-y-3">
@@ -69,11 +69,11 @@ class="block p-4 bg-gray-50 rounded-lg hover:bg-gray-100 transition"
     <div class="mt-12 pt-8 border-t border-gray-200">
         <div class="grid grid-cols-2 gap-4 text-sm text-gray-500">
             <div>
-                <span class="font-medium">Path:</span>
+                <span class="font-medium">{{ __('messages.documents.path') }}:</span>
                 <code class="ml-2 text-xs bg-gray-100 px-2 py-1 rounded">{{ $document->path }}</code>
             </div>
             <div>
-                <span class="font-medium">Last modified:</span>
+                <span class="font-medium">{{ __('messages.documents.last_modified') }}:</span>
                 <span class="ml-2">{{ $document->updated_at->format('Y-m-d H:i:s') }}</span>
             </div>
         </div>

src/resources/views/livewire/quick-switcher.blade.php

@@ -51,7 +51,7 @@ class="w-full max-w-2xl bg-white rounded-lg shadow-2xl"
                             type="text"
                             wire:model.live="search"
                             class="w-full pl-10 pr-4 py-3 border-0 focus:ring-0 text-lg"
-                            placeholder="Search documents..."
+                            placeholder="{{ __('messages.quick_switcher.placeholder') }}"
                             autocomplete="off"
                         >
                     </div>
@@ -61,7 +61,7 @@ class="w-full pl-10 pr-4 py-3 border-0 focus:ring-0 text-lg"
                 <div class="max-h-96 overflow-y-auto">
                     @if(empty($this->results))
                         <div class="p-8 text-center text-gray-500">
-                            No documents found
+                            {{ __('messages.quick_switcher.no_results') }}
                         </div>
                     @else
                         <ul class="divide-y divide-gray-200">
@@ -109,15 +109,15 @@ class="block px-4 py-3 hover:bg-gray-50 transition {{ $index === $selectedIndex
                             <span class="flex items-center">
                                 <kbd class="px-2 py-1 bg-white border border-gray-300 rounded text-xs font-semibold mr-1">↑</kbd>
                                 <kbd class="px-2 py-1 bg-white border border-gray-300 rounded text-xs font-semibold mr-2">↓</kbd>
-                                to navigate
+                                {{ __('messages.quick_switcher.navigate') }}
                             </span>
                             <span class="flex items-center">
                                 <kbd class="px-2 py-1 bg-white border border-gray-300 rounded text-xs font-semibold mr-2">↵</kbd>
-                                to select
+                                {{ __('messages.quick_switcher.select') }}
                             </span>
                             <span class="flex items-center">
                                 <kbd class="px-2 py-1 bg-white border border-gray-300 rounded text-xs font-semibold mr-2">esc</kbd>
-                                to close
+                                {{ __('messages.quick_switcher.close') }}
                             </span>
                         </div>
                     </div>

src/resources/views/livewire/sidebar-tree.blade.php

@@ -1,13 +1,13 @@
 <div class="p-4" x-data="sidebarState()" x-init="initExpandedFolders()">
     <div class="mb-4">
         <h2 class="text-sm font-semibold text-gray-700 uppercase tracking-wider">
-            Documents
+            {{ __('messages.documents.title') }}
         </h2>
     </div>
 
     @if(empty($tree))
         <div class="text-sm text-gray-500 italic">
-            No documents found
+            {{ __('messages.documents.no_documents') }}
         </div>
     @else
         <div class="space-y-1">
@@ -24,7 +24,7 @@ class="flex items-center justify-center px-4 py-2 text-sm font-medium text-white
                 <svg class="w-4 h-4 mr-2" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                     <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 4v16m8-8H4"></path>
                 </svg>
-                New Document
+                {{ __('messages.documents.new_document') }}
             </a>
         </div>
     @endauth

src/resources/views/profile/edit.blade.php

@@ -13,6 +13,12 @@
                 </div>
             </div>
 
+            <div class="p-4 sm:p-8 bg-white shadow sm:rounded-lg">
+                <div class="max-w-xl">
+                    @include('profile.partials.update-locale-form')
+                </div>
+            </div>
+
             <div class="p-4 sm:p-8 bg-white shadow sm:rounded-lg">
                 <div class="max-w-xl">
                     @include('profile.partials.update-password-form')

src/resources/views/profile/partials/update-locale-form.blade.php

@@ -0,0 +1,46 @@
+<section>
+    <header>
+        <h2 class="text-lg font-medium text-gray-900">
+            {{ __('messages.settings.language') }}
+        </h2>
+
+        <p class="mt-1 text-sm text-gray-600">
+            {{ __('messages.settings.select_language') }}
+        </p>
+    </header>
+
+    <form method="post" action="{{ route('locale.update') }}" class="mt-6 space-y-6">
+        @csrf
+
+        <div>
+            <x-input-label for="locale" :value="__('messages.settings.language')" />
+            <select
+                id="locale"
+                name="locale"
+                class="mt-1 block w-full border-gray-300 focus:border-indigo-500 focus:ring-indigo-500 rounded-md shadow-sm"
+            >
+                @foreach(\App\Http\Middleware\SetLocale::SUPPORTED_LOCALES as $code => $name)
+                    <option value="{{ $code }}" {{ (auth()->user()->locale ?? 'en') === $code ? 'selected' : '' }}>
+                        {{ $name }}
+                    </option>
+                @endforeach
+            </select>
+            <x-input-error class="mt-2" :messages="$errors->get('locale')" />
+        </div>
+
+        <div class="flex items-center gap-4">
+            <x-primary-button>{{ __('messages.common.save') }}</x-primary-button>
+
+            @if (session('success'))
+                <p
+                    x-data="{ show: true }"
+                    x-show="show"
+                    x-transition
+                    x-init="setTimeout(() => show = false, 2000)"
+                    class="text-sm text-gray-600"
+                >{{ session('success') }}</p>
+            @endif
+        </div>
+    </form>
+</section>
+

src/routes/web.php

@@ -1,6 +1,7 @@
 <?php
 
 use App\Http\Controllers\ProfileController;
+use App\Http\Controllers\LocaleController;
 use App\Http\Controllers\Admin\UserController as AdminUserController;
 use App\Livewire\DocumentViewer;
 use App\Livewire\DocumentEditor;
@@ -25,6 +26,7 @@
     Route::get('/profile', [ProfileController::class, 'edit'])->name('profile.edit');
     Route::patch('/profile', [ProfileController::class, 'update'])->name('profile.update');
     Route::delete('/profile', [ProfileController::class, 'destroy'])->name('profile.destroy');
+    Route::post('/locale', [LocaleController::class, 'update'])->name('locale.update');
 });
 
 // Admin routes