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/subscription/usage_tracking_modules/usage_stats.py

@@ -0,0 +1,29 @@
+"""
+Usage statistics functions.
+Extracted from usage_tracking_service.py for better maintainability.
+"""
+
+from typing import Dict, Any
+from sqlalchemy.orm import Session
+from loguru import logger
+from datetime import datetime
+
+from models.subscription_models import UsageSummary, UsageStatus, APIProvider
+from services.subscription.usage_tracking_modules.historical_usage import get_all_historical_usage, get_usage_for_period
+
+
+def get_user_usage_stats(user_id: str, billing_period: str, db: Session, pricing_service) -> Dict[str, Any]:
+    """Get comprehensive usage statistics for a user.
+    When no billing_period is specified, returns ALL historical usage data.
+    When a specific period is given, returns only that period's data."""
+    
+    if not user_id:
+        logger.error("get_user_usage_stats called without user_id")
+        raise ValueError("user_id is required")
+    
+    # If no billing_period requested, return ALL historical data
+    if not billing_period:
+        return get_all_historical_usage(user_id, db, pricing_service)
+    
+    # Return data for the specific billing period
+    return get_usage_for_period(user_id, billing_period, db, pricing_service)