Bookability: run date refresh synchronously, update timestamp immediately

Backend now awaits the refresh in a thread executor instead of queuing a
background task, so the response returns only after data is written. Frontend
drops the 3s setTimeout and invalidates the cache immediately on success.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/api/bookability.py

@@ -607,17 +607,18 @@ def _refresh_date_sync(rate_date: date):
 @router.post("/refresh-date/{rate_date}")
 async def refresh_single_date(
     rate_date: str,
-    background_tasks: BackgroundTasks,
     current_user: dict = Depends(get_current_user)
 ):
     """
     Trigger a refresh of rates for a single date from Newbook.
-    Runs in background - returns immediately.
+    Runs synchronously so the client can invalidate its cache immediately on response.
     """
     try:
         target_date = date.fromisoformat(rate_date)
     except ValueError:
         raise HTTPException(status_code=400, detail="Invalid date format. Use YYYY-MM-DD")
 
-    background_tasks.add_task(_refresh_date_sync, target_date)
-    return {"status": "queued", "date": rate_date, "message": f"Refreshing rates for {rate_date}"}
+    import asyncio
+    loop = asyncio.get_event_loop()
+    await loop.run_in_executor(None, _refresh_date_sync, target_date)
+    return {"status": "success", "date": rate_date, "message": f"Rates refreshed for {rate_date}"}

frontend/src/pages/Bookability.tsx

@@ -250,11 +250,8 @@ const Bookability: React.FC = () => {
       return res.data
     },
     onSuccess: () => {
-      // Refetch after a short delay to allow background task to complete
-      setTimeout(() => {
-        queryClient.invalidateQueries({ queryKey: ['rate-matrix'] })
-        setRefreshingDate(null)
-      }, 3000)
+      queryClient.invalidateQueries({ queryKey: ['rate-matrix'] })
+      setRefreshingDate(null)
     },
     onError: () => setRefreshingDate(null),
   })