fix(session): let each CLI declare how its own pane shows work

A Codex session reported `isWorking: false` for its entire life, including
mid-turn. Codeman has four paths that mark a session working, and all four were
inert for Codex:

- The spinner fast path tests eight braille frames, and Codex animates none.
- The activity-streak fallback was wrapped in `!isExternalCliMode(mode)`.
- The pane probe inside `_confirmIdle` would have matched, since Codex prints
  `esc to interrupt`, but arming it required the literal glyph `❯` and Codex
  draws `›` on its composer row.
- The text detector sat inside `_processExpensiveParsers`, whose first statement
  returns early for an external CLI.

Add an optional `workDetect: { promptGlyph, workingLine }` to CliCapabilities,
so the two strings that differ per CLI are registry data rather than constants
in the detector. Claude declares its existing pair and behaves as before. Codex
declares `›` and `esc to interrupt`. The text detector moves above the
external-CLI early return, guarded on the descriptor so a CLI without one still
skips the ANSI strip that the early return used to save it.

A CLI that declares no descriptor falls back to Claude's pair, and the
activity-streak gate now reads "has a descriptor, or is not external", so the
plain shell mode keeps the behaviour it had.

Rewrite the test that asserted the old premise in its own comment, so it makes
the same guarantee for a genuinely uncharacterised CLI, and add Codex coverage
built from verbatim pane captures on Codex CLI 0.152.1.

test/session-activity.test.ts

@@ -1,5 +1,5 @@
 /**
- * Working/idle detection for an interactive Claude pane.
+ * Working/idle detection for an interactive agent pane, Claude's and Codex's.
  *
  * The bug this pins: Claude redraws the composer (`❯`) about once a second all
  * the way through a turn, so the old "saw a ❯, wait 2s, call it idle" rule
@@ -7,11 +7,17 @@
  * worker: `GET /api/sessions` reported `idle` for a session that had been
  * running for 17 minutes and was mid-tool-call.
  *
+ * A second bug this pins: work detection read Claude's glyph and Claude's status line
+ * for every CLI, so a Codex session reported itself idle through an entire turn. Each CLI
+ * now names its own pair in `capabilities.workDetect`, and a CLI that names none reports
+ * work exactly as before.
+ *
  * The status-line fixtures below are verbatim captures from live panes
- * (`tmux -L codeman capture-pane -p`) on Claude Code 2.1.220.
+ * (`tmux -L codeman capture-pane -p`) on Claude Code 2.1.220 and Codex CLI 0.152.1.
  */
 import { describe, expect, it, vi, afterEach } from 'vitest';
 import { Session } from '../src/session.js';
+import { getCli } from '../src/config/cli-registry/index.js';
 import { CLAUDE_WORKING_LINE_PATTERN } from '../src/utils/regex-patterns.js';
 import {
   trackActivityStreak,
@@ -38,7 +44,7 @@ function feed(session: Session, data: string): void {
  * A session whose mux reports a fixed (or scripted) screen, so the pane probe has
  * something to read. Only `capturePaneText` is exercised by these paths.
  */
-function withFakePane(screen: string | (() => string)): Session {
+function withFakePane(screen: string | (() => string), mode: 'claude' | 'codex' = 'claude'): Session {
   const read = typeof screen === 'function' ? screen : () => screen;
   const mux = {
     isAvailable: () => true,
@@ -46,12 +52,26 @@ function withFakePane(screen: string | (() => string)): Session {
   } as unknown as NonNullable<Parameters<typeof Session.prototype.constructor>[0]>['mux'];
   return new Session({
     workingDir: '/tmp',
-    mode: 'claude',
+    mode,
     mux,
     muxSession: { muxName: 'codeman-test', sessionId: 'test', createdAt: Date.now() },
   } as ConstructorParameters<typeof Session>[0]);
 }
 
+/**
+ * Codex's pane, verbatim, while a turn runs and once it has finished. Codex draws `›` on
+ * its composer row through the whole turn, exactly as Claude draws `❯`, and prints
+ * `esc to interrupt` only while the turn is live.
+ */
+const CODEX_WORKING =
+  'Working (2m 49s • esc to interrupt)\n› Ask Codex to do anything\n' +
+  '  gpt-5.6-sol high · Context 59% left · ~/innovi/irisplus-ent-2 · main\n';
+const CODEX_FINISHED =
+  '─ Worked for 3m 47s ────────────────────\n› Ask Codex to do anything\n' +
+  '  gpt-5.6-sol high · Context 57% left · ~/innovi/irisplus-ent-2 · main\n';
+/** Codex's own composer repaint, the frame that arms the idle confirmation. */
+const CODEX_COMPOSER_REPAINT = '\x1b[31;1H\x1b[38;5;246m›\xa0\x1b[39m\x1b[0m';
+
 /** A composer repaint: the frame Claude ships roughly once a second while working. */
 const COMPOSER_REPAINT =
   '\x1b[31;1H\x1b[38;5;246m❯\xa0\x1b[39m\x1b[0m\x1b[33;1H  \x1b[38;5;246mOpus 5  in:143,699 out:669  ctx:14%\x1b[39m';
@@ -230,11 +250,13 @@ describe('Session interactive idle detection', () => {
     expect(session.status).toBe('idle');
   });
 
-  it('does not mark an external CLI pane working off raw activity', () => {
+  it('does not mark an uncharacterised CLI working off raw activity', () => {
     vi.useFakeTimers();
-    // Codex/Gemini/OpenCode render their own TUIs and have no ❯, so nothing would
-    // arm the idle confirmation, so a session marked working here would never recover.
-    const session = new Session({ workingDir: '/tmp', mode: 'codex' });
+    // Gemini and OpenCode render their own TUIs, and Codeman knows neither one's glyph,
+    // so nothing would arm the idle confirmation and a session marked working here would
+    // never recover. A CLI that names no glyph therefore reports no work at all.
+    expect(getCli('gemini')?.capabilities.workDetect).toBeUndefined();
+    const session = new Session({ workingDir: '/tmp', mode: 'gemini' });
     const events: string[] = [];
     session.on('working', () => events.push('working'));
 
@@ -245,6 +267,50 @@ describe('Session interactive idle detection', () => {
 
     expect(events).toEqual([]);
   });
+
+  it('marks a Codex pane working, and lets the turn end', () => {
+    vi.useFakeTimers();
+    let screen = CODEX_WORKING;
+    const session = withFakePane(() => screen, 'codex');
+    const events: string[] = [];
+    session.on('working', () => events.push('working'));
+    session.on('idle', () => events.push('idle'));
+
+    for (let i = 0; i < 3; i++) {
+      feed(session, CODEX_COMPOSER_REPAINT);
+      vi.advanceTimersByTime(1000);
+    }
+    vi.advanceTimersByTime(20_000);
+
+    // The old code reported this session idle for the whole turn.
+    expect(events).toEqual(['working']);
+    expect(session.status).toBe('busy');
+
+    // Turn over: the working footer gives way to the finished line, which must NOT
+    // read as work — it sits on screen for the whole idle period afterwards.
+    screen = CODEX_FINISHED;
+    vi.advanceTimersByTime(20_000);
+
+    expect(events).toEqual(['working', 'idle']);
+    expect(session.status).toBe('idle');
+  });
+});
+
+describe("codex's work-detection descriptor", () => {
+  const codex = getCli('codex')?.capabilities.workDetect;
+
+  it('matches the footer Codex prints while a turn runs', () => {
+    expect(new RegExp(codex!.workingLine).test(CODEX_WORKING)).toBe(true);
+  });
+
+  it('does not match the finished line, nor the idle footer', () => {
+    expect(new RegExp(codex!.workingLine).test(CODEX_FINISHED)).toBe(false);
+  });
+
+  it('names the glyph Codex actually draws on its composer row', () => {
+    expect(CODEX_COMPOSER_REPAINT).toContain(codex!.promptGlyph);
+    expect(CODEX_WORKING).toContain(codex!.promptGlyph);
+  });
 });
 
 describe('wire activity stamp across recovery', () => {