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.

static/js/components/ContextMenu/BulkContextMenu.js

@@ -41,13 +41,9 @@ export class BulkContextMenu extends BaseContextMenu {
         const autoOrganizeItem = this.menu.querySelector('[data-action="auto-organize"]');
         const deleteAllItem = this.menu.querySelector('[data-action="delete-all"]');
         const downloadMissingLorasItem = this.menu.querySelector('[data-action="download-missing-loras"]');
-        const repairMetadataItem = this.menu.querySelector('[data-action="repair-metadata"]');
         const reimportMetadataItem = this.menu.querySelector('[data-action="reimport-metadata"]');
         const rematchMetadataItem = this.menu.querySelector('[data-action="rematch-metadata"]');
 
-        if (repairMetadataItem) {
-            repairMetadataItem.style.display = config.repairMetadata ? 'flex' : 'none';
-        }
         if (reimportMetadataItem) {
             reimportMetadataItem.style.display = config.reimportMetadata ? 'flex' : 'none';
         }
@@ -283,9 +279,6 @@ export class BulkContextMenu extends BaseContextMenu {
             case 'delete-all':
                 bulkManager.showBulkDeleteModal();
                 break;
-            case 'repair-metadata':
-                bulkManager.repairSelectedRecipes();
-                break;
             case 'rematch-metadata':
                 bulkManager.rematchSelectedRecipes();
                 break;