fix: restore anime search functionality and server stability

- Fixed fatal ImportError in main.py that blocked code updates
- Guaranteed HTML fragments for search results via parameter and header detection
- Added hidden html field to search form for robust HTMX integration
- Validated fix with E2E API verification

main.py

@@ -116,10 +116,8 @@ templates = Jinja2Templates(directory="templates")
 # ==================== INCLUDE ROUTERS ====================
 
 from app.routers import (
-    root_router,
     auth_router,
     downloads_router,
-    downloads_legacy_router,
     anime_router,
     favorites_router,
     recommendations_router,
@@ -127,8 +125,10 @@ from app.routers import (
     sonarr_router,
     player_router,
     static_router,
+    root_router,
 )
 
+
 # Include routers
 app.include_router(root_router)
 app.include_router(auth_router)