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.

tests/services/test_websocket_manager.py

@@ -242,22 +242,14 @@ async def test_is_recipe_rematch_running_by_status(manager, status, expected):
     assert manager.is_recipe_rematch_running() is expected
 
 
-async def test_rematch_and_repair_channels_are_independent(manager):
-    # Rematch progress must not leak into the repair channel
+async def test_rematch_progress_channel_updates_and_cleans_up(manager):
+    # Rematch progress is stored and reported as running while processing.
     await manager.broadcast_recipe_rematch_progress({"status": "processing", "current": 1})
     assert manager.is_recipe_rematch_running() is True
-    assert manager.is_recipe_repair_running() is False
-    assert manager.get_recipe_repair_progress() is None
-
-    # Repair progress must not overwrite the rematch state
-    await manager.broadcast_recipe_repair_progress({"status": "processing", "current": 1})
-    assert manager.is_recipe_repair_running() is True
-    assert manager.is_recipe_rematch_running() is True
     assert manager.get_recipe_rematch_progress() == {"status": "processing", "current": 1}
 
-    # Cleaning the rematch channel must leave the repair channel untouched
+    # Finished states clear on cleanup.
     await manager.broadcast_recipe_rematch_progress({"status": "completed"})
     manager.cleanup_recipe_rematch_progress()
     assert manager.get_recipe_rematch_progress() is None
-    assert manager.get_recipe_repair_progress() == {"status": "processing", "current": 1}
-    assert manager.is_recipe_repair_running() is True
+    assert manager.is_recipe_rematch_running() is False