feat(recipes): remove deprecated Repair Metadata feature

The recipe "Repair Metadata" action has been marked Deprecated in the UI
for a while and cannot reliably recover recipes imported from CivitAI URLs
whose REST meta has no resources/hashes and whose image has no embedded
metadata (e.g. CivitAI-only generation data). Drop the feature end to end.

Backend:
- remove repair routes (repair, cancel-repair, recipe/{id}/repair,
  repair-bulk, repair-progress) and their handler mappings/methods
- remove RecipeScanner repair_all_recipes / repair_recipe_by_id /
  _repair_single_recipe and REPAIR_VERSION
- remove WebSocketManager recipe-repair progress channel
- drop repair_version column from the persistent recipe cache
- rematch mutual-exclusion now only checks rematch

Frontend:
- remove repair entries from per-recipe, bulk and global context menus
- remove repairRecipe / repairSelectedRecipes / repairRecipes + cancelRepair
  and the repairBulk API client method/endpoint
- drop recipe-repair i18n keys (synced across locales; doctor keys kept)

Tests/docs: delete test_recipe_repair.py, update scaffolding/routes/ws/
persistent-cache/integration tests and i18n guideline examples.

templates/components/context_menu.html

@@ -94,9 +94,6 @@
         <div class="context-menu-item" data-action="check-updates">
             <i class="fas fa-bell"></i> <span>{{ t('loras.bulkOperations.checkUpdates') }}</span>
         </div>
-        <div class="context-menu-item" data-action="repair-metadata">
-            <i class="fas fa-tools"></i> <span>{{ t('loras.bulkOperations.repairMetadata') }}</span> (Deprecated)
-        </div>
         <div class="context-menu-item" data-action="rematch-metadata">
             <i class="fas fa-link"></i> <span>{{ t('loras.bulkOperations.rematchMetadata') }}</span>
         </div>
@@ -202,9 +199,6 @@
         <i class="fas fa-layer-group"></i> <span>{{ t('globalContextMenu.groupByModel.label') }}</span>
         <i class="fas fa-check check-indicator" style="margin-left:auto;display:none"></i>
     </div>
-    <div class="context-menu-item" data-action="repair-recipes">
-        <i class="fas fa-tools"></i> <span>{{ t('globalContextMenu.repairRecipes.label') }}</span> (Deprecated)
-    </div>
     <div class="context-menu-item" data-action="rematch-recipes">
         <i class="fas fa-link"></i> <span>{{ t('globalContextMenu.rematchRecipes.label') }}</span>
     </div>

templates/recipes.html

@@ -18,9 +18,6 @@
 <div id="recipeContextMenu" class="context-menu" style="display: none;">
     <!-- <div class="context-menu-item" data-action="details"><i class="fas fa-info-circle"></i> View Details</div> -->
     <!-- Metadata -->
-    <div class="context-menu-item" data-action="repair">
-        <i class="fas fa-tools"></i> {{ t('loras.contextMenu.repairMetadata') }} (Deprecated)
-    </div>
     <div class="context-menu-item" data-action="rematch">
         <i class="fas fa-link"></i> {{ t('loras.contextMenu.rematchMetadata') }}
     </div>