fix: WYSIWYG editor, content generation, and writing assistant bug fixes

- Fix text selection menu not showing: wire contentRef via inputRef on multiline TextField
- Fix blog title not truncating: add min-w-0 for flex item overflow
- Fix outline generation 500: escape curly braces in f-string prompt template
- Fix content generation 'NoneType not callable': replace SessionLocal() with get_session_for_user(), add db param to MediumBlogGenerator, fix signature mismatch in database_task_manager
- Fix writing assistant suggest 500: add auth + user_id to API endpoint and service, replace sync requests with httpx.AsyncClient
- Fix hallucination detector 404: explicitly include router in main.py and app.py
- Fix missing error_data in task failure responses
- Hide CopilotKit web inspector button
- Remove hardcoded fallback suggestions from SmartTypingAssist
- Fix stale closure refs in SmartTypingAssist handleTypingChange
- Add two-column editor layout, stats bar, section hover menu
- Various subscription, billing, and research module improvements

backend/services/blog_writer/research/tavily_provider.py

@@ -135,11 +135,14 @@ class TavilyResearchProvider(BaseProvider):
     
     def track_tavily_usage(self, user_id: str, cost: float, search_depth: str):
         """Track Tavily API usage after successful call."""
-        from services.database import get_db
+        from services.database import get_session_for_user
         from services.subscription import PricingService
         from sqlalchemy import text
         
-        db = next(get_db())
+        db = get_session_for_user(user_id)
+        if not db:
+            logger.warning(f"[Tavily] Could not get DB session for user {user_id}, skipping usage tracking")
+            return
         try:
             pricing_service = PricingService(db)
             current_period = pricing_service.get_current_billing_period(user_id)