fix(agent-browser): restore bounded presentation lifecycle

tests/unit/coding-composition-background-sleep.test.ts

@@ -17,6 +17,36 @@ afterEach(async () => {
 });
 
 describe('coding composition background sleep', () => {
+  it('closes the shared browser before an idle background runtime sleeps', async () => {
+    const projectPath = await mkdtemp(path.join(tmpdir(), 'makelore-sleep-browser-project-'));
+    const userDataDir = await mkdtemp(path.join(tmpdir(), 'makelore-sleep-browser-user-'));
+    roots.push(projectPath, userDataDir);
+    const close = vi.fn(async () => undefined);
+    const composition = createCodingComposition({
+      storage: createMemoryCodingProjectStorage(),
+      browser: { close } as unknown as AgentBrowserModule,
+      paths: {
+        executablePath: process.execPath,
+        cliPath: path.join(projectPath, 'unused-cli.js'),
+        serverPath: path.join(projectPath, 'unused-server.mjs'),
+        userDataDir,
+        bundledSkillsDir: path.resolve('resources/coding-skills'),
+      },
+    });
+    const stopAgentServer = vi.spyOn(PiAgentServerProcess.prototype, 'stop')
+      .mockResolvedValue(undefined);
+
+    try {
+      await composition.sleep('background_sleep');
+
+      expect(close).toHaveBeenCalledTimes(1);
+      expect(stopAgentServer).toHaveBeenCalledTimes(1);
+    } finally {
+      stopAgentServer.mockRestore();
+      await composition.shutdown();
+    }
+  });
+
   it('does not stop the shared Agent Server when work starts during worker cleanup', async () => {
     const projectPath = await mkdtemp(path.join(tmpdir(), 'makelore-sleep-race-project-'));
     const userDataDir = await mkdtemp(path.join(tmpdir(), 'makelore-sleep-race-user-'));