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

test_watchlist_simple.py

@@ -50,7 +50,7 @@ def test_watchlist_basics():
     )
 
     try:
-        item = watchlist_manager.create(test_user, item_data)
+        item = watchlist_manager.add(test_user, item_data)
         print(f"   ✅ Item created: {item.id}")
         print(f"   Title: {item.anime_title}")
         print(f"   Status: {item.status}")
@@ -178,7 +178,7 @@ async def test_scheduler():
     print("🧪 TEST 3: Auto-Download Scheduler")
     print("="*60)
 
-    print("\n1. Testing scheduler start (async)...")
+    print("\n1. Testing scheduler start...")
     try:
         auto_download_scheduler.start()
         print(f"   ✅ Scheduler started")