Implement ID-based routing and folder auto-generation from titles

Major features:
- Switch from slug-based to ID-based routing (/documents/123)
- Enable title editing with automatic slug/path regeneration
- Auto-generate folder structure from title slashes (e.g., Laravel/Livewire/Components)
- Persist sidebar folder open/close state using localStorage
- Remove slug unique constraint (ID routing makes it unnecessary)
- Implement recursive tree view with multi-level folder support

Architecture changes:
- DocumentService: Add generatePathAndSlug() for title-based path generation
- Routes: Change from {document:slug} to {document} for ID binding
- SidebarTree: Extract recursive rendering to partials/tree-item.blade.php
- Database: Remove unique constraint from documents.slug column

UI improvements:
- Display only last path component in sidebar (Components vs Laravel/Livewire/Components)
- Folder state persists across page navigation via localStorage
- Title field accepts slashes for folder organization

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/routes/web.php

@@ -0,0 +1,40 @@
+<?php
+
+use App\Http\Controllers\ProfileController;
+use App\Livewire\DocumentViewer;
+use App\Livewire\DocumentEditor;
+use App\Models\Document;
+use Illuminate\Support\Facades\Route;
+
+Route::get('/', function () {
+    $homeDocument = Document::where('slug', 'home')->first();
+
+    if ($homeDocument) {
+        return redirect()->route('documents.show', $homeDocument);
+    }
+
+    return view('welcome');
+});
+
+Route::get('/dashboard', function () {
+    return view('dashboard');
+})->middleware(['auth', 'verified'])->name('dashboard');
+
+Route::middleware('auth')->group(function () {
+    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::prefix('documents')->name('documents.')->group(function () {
+    // 認証が必要なルート（より具体的なルートを先に定義）
+    Route::middleware('auth')->group(function () {
+        Route::get('/create', DocumentEditor::class)->name('create');
+        Route::get('/{document}/edit', DocumentEditor::class)->name('edit');
+    });
+
+    // 公開ルート（動的ルートは最後に）
+    Route::get('/{document}', DocumentViewer::class)->name('show');
+});
+
+require __DIR__.'/auth.php';