feat(recipe): add reimport endpoint to re-import recipe from source URL

Adds POST /api/lm/recipe/{recipe_id}/reimport that atomically:
1. Reads the existing recipe to extract source_url and user edits
2. Deletes the old recipe files and cache entries
3. Re-downloads the image from CivitAI, re-parses EXIF metadata
4. Carries over user edits (title, tags, favorite) and timestamps

py/routes/recipe_route_registrar.py

@@ -78,6 +78,9 @@ ROUTE_DEFINITIONS: tuple[RouteDefinition, ...] = (
     RouteDefinition(
         "POST", "/api/lm/recipes/create-from-example", "create_from_example"
     ),
+    RouteDefinition(
+        "POST", "/api/lm/recipe/{recipe_id}/reimport", "reimport_recipe"
+    ),
 )