fix: multiple bug fixes

isolated users, db backup, weird disconnect issues for long voice sessions,

server/src/websocket/handler-status.spec.ts

@@ -67,6 +67,14 @@ describe('server websocket handler - status_update', () => {
     connectedUsers.clear();
   });
 
+  it('treats signaling keepalive messages as connection liveness', async () => {
+    createConnectedUser('conn-1', 'user-1', { lastPong: 1 });
+
+    await handleWebSocketMessage('conn-1', { type: 'keepalive' });
+
+    expect(connectedUsers.get('conn-1')?.lastPong).toBeGreaterThan(1);
+  });
+
   it('updates user status on valid status_update message', async () => {
     const user = createConnectedUser('conn-1', 'user-1');