Update statistics panel to show data for the current month only

Fix StatsPanel component to use a passed-in currentDate prop, defaulting to new Date(), and update Calendar page to pass currentDate to StatsPanel. Refactor useQuery to include fetch logic.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: b163d4c0-de5e-4f4e-a9c0-aed4c7049718
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/1957c339-2757-4d1f-8e92-e9f71a1ce58e/b163d4c0-de5e-4f4e-a9c0-aed4c7049718/r0JXGx6

client/src/pages/Calendar.tsx

@@ -267,7 +267,7 @@ export default function Calendar() {
       )}
 
       {/* Stats Panel */}
-      <StatsPanel />
+      <StatsPanel currentDate={currentDate} />
     </div>
   );
 }