fix(codex): harden model discovery fallback

cli/src/codex/codexAppServerClient.test.ts

@@ -0,0 +1,64 @@
+import { EventEmitter } from 'node:events';
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+const { execFileSyncMock, spawnMock } = vi.hoisted(() => ({
+    execFileSyncMock: vi.fn(() => 'codex-cli 1.0.0'),
+    spawnMock: vi.fn()
+}));
+
+vi.mock('node:child_process', async () => {
+    const actual = await vi.importActual<typeof import('node:child_process')>('node:child_process');
+    return {
+        ...actual,
+        execFileSync: execFileSyncMock,
+        spawn: spawnMock
+    };
+});
+
+vi.mock('node:fs', async () => {
+    const actual = await vi.importActual<typeof import('node:fs')>('node:fs');
+    return { ...actual, existsSync: vi.fn(() => false) };
+});
+
+vi.mock('@/utils/process', () => ({
+    killProcessByChildProcess: vi.fn(async () => true)
+}));
+
+vi.mock('@/ui/logger', () => ({
+    logger: { debug: vi.fn() }
+}));
+
+import { CodexAppServerClient } from './codexAppServerClient';
+
+function fakeStream(): EventEmitter & { setEncoding: ReturnType<typeof vi.fn> } {
+    return Object.assign(new EventEmitter(), { setEncoding: vi.fn() });
+}
+
+function fakeChild() {
+    return Object.assign(new EventEmitter(), {
+        stdin: { end: vi.fn(), write: vi.fn() },
+        stdout: fakeStream(),
+        stderr: fakeStream()
+    });
+}
+
+describe('CodexAppServerClient process cwd', () => {
+    beforeEach(() => {
+        execFileSyncMock.mockClear();
+        spawnMock.mockReset();
+    });
+
+    it('passes an explicit neutral cwd to the app-server process', async () => {
+        spawnMock.mockReturnValue(fakeChild());
+        const client = new CodexAppServerClient({ cwd: '/neutral-home' });
+
+        await client.connect();
+
+        expect(spawnMock).toHaveBeenCalledWith(
+            'codex',
+            ['app-server'],
+            expect.objectContaining({ cwd: '/neutral-home' })
+        );
+        await client.disconnect();
+    });
+});