feat: instrument telemetry for dev command

Add telemetry recording to the dev command across all execution paths:
- Invoke: wrapped with withCommandRunTelemetry, emits on success/failure
- Exec: wrapped with withCommandRunTelemetry for container exec
- Server modes (--logs, --no-browser, browser): emit on SIGINT/exit

Schema changes:
- Expand Action enum to include 'exec'
- Add UiMode enum ('browser' | 'terminal')
- Add 'agui' to Protocol enum
- Add ui_mode field to DevAttrs

Refactored invoke helpers to throw instead of process.exit(1) so
telemetry wrapper can record failures before exit.

Attributes emitted: action, ui_mode, has_stream, protocol, invoke_count

Author: Hweinstock

integ-tests/dev-server.test.ts

@@ -1,4 +1,4 @@
-import { runCLI } from '../src/test-utils/index.js';
+import { createTelemetryHelper, runCLI } from '../src/test-utils/index.js';
 import { type ChildProcess, execSync, spawn } from 'node:child_process';
 import { randomUUID } from 'node:crypto';
 import { mkdir, rm } from 'node:fs/promises';
@@ -38,6 +38,8 @@ describe('integration: dev server', () => {
   let projectPath: string;
   let devProcess: ChildProcess | null = null;
 
+  const telemetry = createTelemetryHelper();
+
   beforeAll(async () => {
     testDir = join(tmpdir(), `agentcore-integ-dev-${randomUUID()}`);
     await mkdir(testDir, { recursive: true });
@@ -81,6 +83,7 @@ describe('integration: dev server', () => {
     if (devProcess) {
       devProcess.kill('SIGKILL');
     }
+    telemetry.destroy();
     await rm(testDir, { recursive: true, force: true });
   });
 
@@ -101,6 +104,31 @@ describe('integration: dev server', () => {
       const serverReady = await waitForServer(port, 20000);
       expect(serverReady, 'Dev server should respond to ping within 20s').toBeTruthy();
 
+      // Invoke the running server and verify telemetry
+      const invokeResult = await runCLI(['dev', 'hello', '--port', String(port)], projectPath, {
+        env: telemetry.env,
+      });
+      expect(invokeResult.exitCode).toBe(0);
+
+      telemetry.assertMetricEmitted({
+        command: 'dev',
+        action: 'invoke',
+        ui_mode: 'terminal',
+        exit_reason: 'success',
+        protocol: 'http',
+      });
+
+      // Verify failure telemetry when invoking a non-running port
+      telemetry.clearEntries();
+      const failResult = await runCLI(['dev', 'hello', '--port', '19999'], projectPath, { env: telemetry.env });
+      expect(failResult.exitCode).toBe(1);
+
+      telemetry.assertMetricEmitted({
+        command: 'dev',
+        action: 'invoke',
+        exit_reason: 'failure',
+      });
+
       // Clean shutdown
       devProcess.kill('SIGTERM');
       devProcess = null;