Add documents.delete_translation lang key for editor button

The editor's delete-translation button used `__('messages.documents.delete_translation') ?? __('messages.documents.delete')`, but `__()` returns the key string (not null) on miss so the `??` fallback never fires — the button rendered the literal key. Adds the missing key to all 16 locales (en+ja human-translated, others mirror en) and simplifies the blade to a single `__()` call.

Plan doc also reflects the SQLite dropIndex requirement found during Task 2.

docs/superpowers/plans/2026-05-10-article-i18n.md

@@ -369,8 +369,10 @@ return new class extends Migration
             DB::statement('ALTER TABLE documents DROP INDEX documents_search_index');
         }
 
-        // 5. Drop translatable columns from documents
+        // 5. Drop translatable columns from documents.
+        //    SQLite requires explicit dropIndex on the title index before dropColumn.
         Schema::table('documents', function (Blueprint $table) {
+            $table->dropIndex(['title']);
             $table->dropColumn(['title', 'content', 'rendered_html']);
         });
     }

src/lang/de/messages.php

@@ -44,6 +44,7 @@
         'translation_added' => 'Translation added.',
         'translation_deleted' => 'Translation deleted.',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

src/lang/en/messages.php

@@ -44,6 +44,7 @@
         'fallback_notice' => 'A translation in your selected language is not available. Showing the :locale version.',
         'add_translation' => 'Add translation',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

src/lang/es/messages.php

@@ -44,6 +44,7 @@
         'translation_added' => 'Translation added.',
         'translation_deleted' => 'Translation deleted.',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

src/lang/fr/messages.php

@@ -44,6 +44,7 @@
         'translation_added' => 'Translation added.',
         'translation_deleted' => 'Translation deleted.',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

src/lang/hi/messages.php

@@ -44,6 +44,7 @@
         'translation_added' => 'Translation added.',
         'translation_deleted' => 'Translation deleted.',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

src/lang/it/messages.php

@@ -44,6 +44,7 @@
         'translation_added' => 'Translation added.',
         'translation_deleted' => 'Translation deleted.',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

src/lang/ja/messages.php

@@ -44,6 +44,7 @@
         'fallback_notice' => 'この記事には選択した言語の翻訳がありません。元の言語版を表示しています。',
         'add_translation' => '翻訳を追加',
         'set_as_default' => 'デフォルトに設定',
+        'delete_translation' => '翻訳を削除',
         'delete_translation_blocked' => 'デフォルト言語の翻訳は削除できません。',
         'translation_tabs_label' => '言語',
     ],

src/lang/ko/messages.php

@@ -44,6 +44,7 @@
         'translation_added' => 'Translation added.',
         'translation_deleted' => 'Translation deleted.',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

src/lang/pl/messages.php

@@ -44,6 +44,7 @@
         'translation_added' => 'Translation added.',
         'translation_deleted' => 'Translation deleted.',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

src/lang/pt-BR/messages.php

@@ -44,6 +44,7 @@
         'translation_added' => 'Translation added.',
         'translation_deleted' => 'Translation deleted.',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

src/lang/ru/messages.php

@@ -44,6 +44,7 @@
         'translation_added' => 'Translation added.',
         'translation_deleted' => 'Translation deleted.',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

src/lang/tr/messages.php

@@ -44,6 +44,7 @@
         'translation_added' => 'Translation added.',
         'translation_deleted' => 'Translation deleted.',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

src/lang/uk/messages.php

@@ -44,6 +44,7 @@
         'translation_added' => 'Translation added.',
         'translation_deleted' => 'Translation deleted.',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

src/lang/vi/messages.php

@@ -44,6 +44,7 @@
         'translation_added' => 'Translation added.',
         'translation_deleted' => 'Translation deleted.',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

src/lang/zh-CN/messages.php

@@ -44,6 +44,7 @@
         'translation_added' => 'Translation added.',
         'translation_deleted' => 'Translation deleted.',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

src/lang/zh-TW/messages.php

@@ -44,6 +44,7 @@
         'translation_added' => 'Translation added.',
         'translation_deleted' => 'Translation deleted.',
         'set_as_default' => 'Set as default',
+        'delete_translation' => 'Delete translation',
         'delete_translation_blocked' => 'The default-language translation cannot be deleted.',
         'translation_tabs_label' => 'Languages',
     ],

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

@@ -108,7 +108,7 @@ class="px-2 py-1 text-xs text-indigo-600 border border-indigo-300 rounded hover:
                             wire:confirm="{{ __('messages.documents.delete_confirm') }}"
                             type="button"
                             class="px-2 py-1 text-xs text-red-600 border border-red-300 rounded hover:bg-red-50">
-                        {{ __('messages.documents.delete_translation') ?? __('messages.documents.delete') }}
+                        {{ __('messages.documents.delete_translation') }}
                     </button>
                 </div>
             @endif