re-land the client half: hold the socket across a remount, and queue what was typed

Three commits backed out a few hours ago as collateral, restored together because they are one fix:
243bd04 (queue sends until OPEN), bc13450 (defer the teardown close by a tick, cancellable) and
66a41d0 (count CONNECTING as ours, not only OPEN).

Why they are needed, from evidence rather than reasoning. d9857ee fixed the server side and Andre
still had nothing on https://macbook.pastilhas.dev after a restart. The decisive observation is an
ABSENCE: his attempts appear nowhere in officer's log — no "Model selected for chat", no
claude:stream for his session. Nothing reaches the server at all. Meanwhile a socket I drove by hand
against the same wss:// url ran a full turn in 2.5s, so the transport is not it.

That is `send` dropping the message. It returned silently on `readyState !== OPEN`, and the socket is
not OPEN because the effect cleanup closed it on a remount while it was still CONNECTING, then closed
its replacement the same way. Enter does nothing, forever, with the view sitting on Disconnected —
and no error anywhere, on either side, which is why this reads as a dead server.

Note what is still NOT fixed, and is written into the code comment rather than this message alone: a
/chat/new load opens TWO sockets, from two separate useChat instances mounting. Measured with a
constructor counter. Both connect, so it looks healthy; d9857ee is what makes it harmless.

Correction to d9857ee's message, so the record is not wrong: it claims the localhost/domain split is
latency changing the attach/close ordering. That is plausible and it is NOT what was demonstrated —
the server-side fix alone did not help. It is still worth having (a stale close silencing a live
client is real, and so is the idle GC gate), but the asymmetry is unexplained and the client drop
above is what actually stopped a message.

Client bundle changes, so this needs a hard reload as well as a restart. Not verified in a browser.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/workspaces/hooks/src/useChatWebSocket.ts

@@ -15,14 +15,39 @@ export const useChatWebSocket = ({ url, onMessage, onOpen }: UseChatWebSocketPar
   const retryRef = useRef(0);
   const retryTimeoutRef = useRef<number | null>(null);
   const isCleaningUpRef = useRef(false);
+  /** A deferred teardown, cancelled when the effect re-runs — see the cleanup below. */
+  const closeTimerRef = useRef<number | null>(null);
   const onMessageRef = useRef(onMessage);
   onMessageRef.current = onMessage;
   const onOpenRef = useRef(onOpen);
   onOpenRef.current = onOpen;
 
+  /**
+   * Messages typed before the socket was ready.
+   *
+   * `send` used to drop them: `readyState !== OPEN` returned, silently, with no error and no retry — so
+   * pressing enter did nothing and the turn never happened. That window is not rare. React's dev
+   * StrictMode double-invokes effects, so every socket is created, closed and recreated on mount, and a
+   * reconnect after a drop reopens it again; with several chat panes on screen there are several sockets
+   * doing this at once. One of them is always briefly not OPEN.
+   *
+   * Queued and flushed on open, in order. The mobile chat app does exactly this and for exactly this
+   * reason — the composer is allowed to fire before the transport is ready.
+   */
+  const pendingRef = useRef<string[]>([]);
+
   const connect = () => {
     if (isCleaningUpRef.current) return;
-    if (socketRef.current && socketRef.current.readyState === WebSocket.OPEN) return;
+    // CONNECTING counts as ours, not just OPEN. The deferred teardown below keeps a remount's socket
+    // alive mid-handshake, and this is what reclaims it: checking only OPEN meant an effect re-run
+    // built a SECOND socket and orphaned the first, which then stayed open forever with its own `open`
+    // handler bailing on the socketRef mismatch.
+    //
+    // This is per-instance and does NOT explain the two sockets a /chat/new load opens — measured with
+    // a WebSocket-constructor counter, those come from two separate `useChat` instances mounting, each
+    // with its own refs. Unresolved, and tracked separately; both connect, so it reads as healthy.
+    const existing = socketRef.current;
+    if (existing && (existing.readyState === WebSocket.OPEN || existing.readyState === WebSocket.CONNECTING)) return;
 
     const socket = new WebSocket(url);
     socketRef.current = socket;
@@ -31,7 +56,12 @@ export const useChatWebSocket = ({ url, onMessage, onOpen }: UseChatWebSocketPar
       if (socketRef.current !== socket) return;
       setIsConnected(true);
       retryRef.current = 0;
+      // BEFORE onOpen, deliberately: onOpen sends the resume/attach handshake, and anything the user
+      // typed while connecting belongs after that, not in front of it.
+      const queued = pendingRef.current;
+      pendingRef.current = [];
       onOpenRef.current?.();
+      for (const message of queued) socket.send(message);
     });
 
     socket.addEventListener('message', (ev) => {
@@ -59,25 +89,56 @@ export const useChatWebSocket = ({ url, onMessage, onOpen }: UseChatWebSocketPar
   };
 
   useEffect(() => {
+    // A pending teardown from a remount that is about to be undone — see below.
+    if (closeTimerRef.current !== null) {
+      clearTimeout(closeTimerRef.current);
+      closeTimerRef.current = null;
+    }
     isCleaningUpRef.current = false;
     connect();
+
     return () => {
+      /**
+       * Close LATER, not now.
+       *
+       * Closing here directly is correct for a real unmount and disastrous for a remount, and this hook
+       * cannot tell them apart at the moment it runs. React's dev StrictMode double-invokes every effect
+       * (mount → unmount → mount), and a subtree that is re-created — a resolved transcript, a parent key
+       * change — does the same. Each time, the socket was closed while still CONNECTING, the browser
+       * logged "closed before the connection is established", and the replacement was closed in turn, so
+       * the view could churn forever and never hold a connection while sitting on Disconnected.
+       *
+       * Deferring by a tick makes the two distinguishable. A remount re-runs the effect immediately and
+       * cancels this timer, so the live socket is kept and the handshake completes. A real unmount has
+       * nobody to cancel it and the socket closes a frame later, which costs nothing.
+       */
       isCleaningUpRef.current = true;
       if (retryTimeoutRef.current !== null) {
         clearTimeout(retryTimeoutRef.current);
         retryTimeoutRef.current = null;
       }
-      if (socketRef.current) {
-        socketRef.current.close();
-        socketRef.current = null;
-      }
+      const socket = socketRef.current;
+      closeTimerRef.current = window.setTimeout(() => {
+        closeTimerRef.current = null;
+        if (!isCleaningUpRef.current) return; // remounted: the effect above already reclaimed it
+        if (socket) socket.close();
+        if (socketRef.current === socket) socketRef.current = null;
+      }, 0);
     };
   }, [url]);
 
   const send = (data: Record<string, unknown>) => {
     const socket = socketRef.current;
-    if (!socket || socket.readyState !== WebSocket.OPEN) return;
-    socket.send(JSON.stringify(data));
+    const message = JSON.stringify(data);
+    if (socket && socket.readyState === WebSocket.OPEN) {
+      socket.send(message);
+      return;
+    }
+    // Not open yet, or reconnecting. Hold it rather than dropping it — see `pendingRef`. Bounded so a
+    // socket that never comes back cannot grow this without limit; the oldest go first, because the
+    // newest message is the one the user is still waiting on.
+    pendingRef.current.push(message);
+    if (pendingRef.current.length > 50) pendingRef.current.shift();
   };
 
   return { isConnected, send };