Fix API errors and improve customer discovery with real web results

- Fix usage/stats 500: use Date() not datetime.date() for SQL cast
- Fix customers 422: raise size limit to 1000
- Replace unreliable MCP client with direct Bing batch search for discovery
- Batch all search queries in one browser session (faster)
- Show real company names/URLs from Bing, not generic templates
- Smart filter for non-business results (news, blogs, forums)
- Fallback suggestions when search results are insufficient
- Frontend: clickable contact URLs, provider indicator, better layout

backend/app/api/v1/customer.py

@@ -17,7 +17,7 @@ router = APIRouter()
 async def list_customers(
     status: Optional[str] = None,
     page: int = Query(1, ge=1),
-    size: int = Query(20, ge=1, le=100),
+    size: int = Query(20, ge=1, le=1000),
     user_id: str = Depends(get_current_user_id),
     db: AsyncSession = Depends(get_db),
 ):