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.

py/services/persistent_recipe_cache.py

@@ -52,7 +52,6 @@ class PersistentRecipeCache:
         "file_mtime",
         "file_size",
         "favorite",
-        "repair_version",
         "preview_nsfw_level",
         "loras_json",
         "checkpoint_json",
@@ -442,7 +441,6 @@ class PersistentRecipeCache:
                             file_mtime REAL,
                             file_size INTEGER,
                             favorite INTEGER DEFAULT 0,
-                            repair_version INTEGER DEFAULT 0,
                             preview_nsfw_level INTEGER DEFAULT 0,
                             loras_json TEXT,
                             checkpoint_json TEXT,
@@ -541,7 +539,6 @@ class PersistentRecipeCache:
             file_mtime,
             file_size,
             1 if recipe.get("favorite") else 0,
-            int(recipe.get("repair_version") or 0),
             int(recipe.get("preview_nsfw_level") or 0),
             loras_json,
             checkpoint_json,
@@ -599,7 +596,6 @@ class PersistentRecipeCache:
             "created_date": row["created_date"] or 0.0,
             "modified": row["modified"] or 0.0,
             "favorite": bool(row["favorite"]),
-            "repair_version": row["repair_version"] or 0,
             "preview_nsfw_level": row["preview_nsfw_level"] or 0,
             "has_workflow": bool(row["has_workflow"]),
             "loras": loras,