Increase handover drain timeout from 5 minutes to 24 hours

The 5-minute drain timeout was too aggressive — long-running queries
were being forcibly terminated during rolling deployments. Increase to
24 hours so existing connections can finish naturally.

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

Author: fuziontech

controlplane/handover.go

@@ -190,8 +190,8 @@ func (cp *ControlPlane) handleHandoverRequest(conn net.Conn, handoverLn net.List
 	select {
 	case <-drainDone:
 		slog.Info("All connections drained after handover.")
-	case <-time.After(5 * time.Minute):
-		slog.Warn("Handover drain timeout after 5 minutes, forcing exit.")
+	case <-time.After(24 * time.Hour):
+		slog.Warn("Handover drain timeout after 24 hours, forcing exit.")
 	}
 
 	// Shut down workers