fix(discord): say when the agent has exited, keep replies in order, settle a stalled response, prune dead tabs

- a reply to a tab whose agent has exited is answered in the thread, with no tick
- inbound messages run on one chain per thread, so a reply with a file cannot be overtaken
- postJson settles when a response stalls after its headers
- the thread map is pruned against the live sessions once after boot

test/cli-notify.test.ts

@@ -71,6 +71,21 @@ describe('runNotify', () => {
     }
   });
 
+  it('postJson settles when the server sends headers and then stalls the body', async () => {
+    const server = createServer((_req, res) => {
+      res.writeHead(200, { 'Content-Type': 'application/json', 'Content-Length': '500' });
+      res.write('{"success":');
+    });
+    await new Promise<void>((r) => server.listen(0, '127.0.0.1', r));
+    try {
+      const { port } = server.address() as AddressInfo;
+      expect((await postJson(`http://127.0.0.1:${port}`, '/x', {}, 100)).status).toBe(0);
+    } finally {
+      server.closeAllConnections();
+      server.close();
+    }
+  });
+
   it('treats a disabled bridge (409) as success that says so', async () => {
     const r = await runNotify({ message: 'x' }, ENV, '/work', fake(409));
     expect(r.code).toBe(0);

test/discord-bridge.test.ts

@@ -551,6 +551,17 @@ describe('DiscordBridge', () => {
     b.stop();
   });
 
+  it('prune drops thread entries for tabs that no longer exist, and keeps the live ones', async () => {
+    const b = bridge();
+    await b.notify(MSG);
+    await b.notify({ ...MSG, sessionId: 's2', sessionName: 'w2' });
+    await b.prune(['s2']);
+    expect(Object.keys(await readThreadMap(dir))).toEqual(['s2']);
+    await b.prune([]); // nothing restored: leave the map alone
+    expect(Object.keys(await readThreadMap(dir))).toEqual(['s2']);
+    b.stop();
+  });
+
   describe('sendTest', () => {
     it('posts with the config it is given and leaves the live config alone', async () => {
       const auth: string[] = [];
@@ -734,7 +745,8 @@ describe('DiscordBridge files and startup hint', () => {
   function make(
     cfg: Partial<DiscordConfig> = {},
     dirFor: (id: string) => string | undefined = () => work,
-    awaitingChoice?: (id: string) => boolean
+    awaitingChoice?: (id: string) => boolean,
+    agentExited?: (id: string) => boolean
   ) {
     const b = new DiscordBridge({
       configDir: dir,
@@ -751,6 +763,7 @@ describe('DiscordBridge files and startup hint', () => {
       sendInput: async (id, text, fromUser) => (sent.push([id, text, fromUser]), true),
       sessionDir: dirFor,
       awaitingChoice,
+      agentExited,
       socketFactory: () => new FakeSocket(),
       now: () => t,
       sleep: async () => undefined,
@@ -834,6 +847,26 @@ describe('DiscordBridge files and startup hint', () => {
     b.stop();
   });
 
+  it('says the agent has exited and types nothing when the tab reports it', async () => {
+    const b = await make({}, undefined, undefined, () => true);
+    await b.onGatewayMessage(reply({ content: 'hello', attachments: [] }));
+    expect(sent).toHaveLength(0);
+    expect(String(posted.at(-1)?.body?.content)).toMatch(/exited/);
+    expect(posted.some((p) => p.path.includes('reactions'))).toBe(false);
+    b.stop();
+  });
+
+  it('types a reply that waits on a download before a later text reply', async () => {
+    const b = await make();
+    const slow = b.onGatewayMessage(reply({ content: 'first' }));
+    await new Promise((r) => setTimeout(r, 0)); // the first reply is under way (gate passed) before the clock moves
+    t += 5_000;
+    const fast = b.onGatewayMessage(reply({ id: '555555555555555556', content: 'second', attachments: [] }));
+    await Promise.all([slow, fast]);
+    expect(sent.map((s) => s[1].split(' ')[0])).toEqual(['first', 'second\r']);
+    b.stop();
+  });
+
   it('types a lone digit without Enter while a dialog is waiting, and with Enter otherwise', async () => {
     let waiting = true;
     const b = await make({}, undefined, () => waiting);

test/discord-push-glue.test.ts

@@ -43,6 +43,20 @@ function server(): Internals {
 
 beforeEach(() => sendNotification.mockClear());
 
+describe('bridge deps', () => {
+  it('agentExited is true only for a session whose pane exit was observed', () => {
+    const s = new WebServer(0, false, true, '127.0.0.1', 'box') as unknown as Internals & {
+      discordBridge: { deps: { agentExited: (id: string) => boolean } };
+    };
+    s.sessions.set('dead', { paneExit: { observedAt: 1 } });
+    s.sessions.set('alive', {});
+    const { agentExited } = s.discordBridge.deps;
+    expect(agentExited('dead')).toBe(true);
+    expect(agentExited('alive')).toBe(false);
+    expect(agentExited('missing')).toBe(false);
+  });
+});
+
 describe('sendPushNotifications -> Discord', () => {
   it('posts a permission prompt with zero push subscriptions, with the rendered screen as the tail', async () => {
     const s = server();