fix(realtime): resync active chat messages on websocket reconnect

- on ws reconnect, reload chats and active chat history
- reduce status/history drift after transient disconnects

web/src/hooks/useRealtime.ts

@@ -62,7 +62,11 @@ export function useRealtime() {
             ws.close();
           }
         }, 15000);
-        void useChatStore.getState().loadChats();
+        const store = useChatStore.getState();
+        void store.loadChats();
+        if (store.activeChatId) {
+          void store.loadMessages(store.activeChatId);
+        }
       };
 
       ws.onmessage = (messageEvent) => {