fix: migrations, auth, providers health check, E2E tests, remove neko-sama

- Add proper Alembic initial migration (0001_initial_schema.py)
- Migrate refresh tokens from JSON file to SQLite (RefreshTokenTable)
- Remove Neko-Sama provider entirely (redirects to Gupy, not a host)
- Fix provider health check always showing UNKNOWN
  - Run check_all_health() on startup
  - Fix POST /providers/health/check background task bug
  - Add HTMX refresh after manual health check trigger
- Fix anime search relevance scoring with MIN_RELEVANCE_THRESHOLD=0.5
- Replace bare 'except:' with 'except Exception:' across codebase
- Add Playwright E2E test suite (12 tests, auth setup, helpers)
- Fix toast container blocking clicks via pointer-events: none
- Remove obsolete Jest/Vite test files and config
- Clean up obsolete test_watchlist scripts
- Update sonarr model comment for active providers

tests/test_api.py

@@ -426,7 +426,7 @@ class TestAPIFavorites:
         # Make sure it doesn't exist first
         try:
             client.delete("/api/favorites/test-toggle-add")
-        except:
+        except Exception:
             pass
 
         response = client.post(
@@ -448,7 +448,7 @@ class TestAPIFavorites:
         # Make sure it doesn't exist first
         try:
             client.delete("/api/favorites/test-toggle-remove")
-        except:
+        except Exception:
             pass
 
         # Add first