fix: clean stale pid on stop (#1015)

tests/server/cli-port-detection.test.ts

@@ -125,6 +125,22 @@ describe('CLI port detection', () => {
     }
   })
 
+  it('cleans a stale server PID file during stop', async () => {
+    const home = mkdtempSync(join(tmpdir(), 'hermes-web-ui-cli-stale-pid-'))
+    process.env.HERMES_WEB_UI_HOME = home
+    const pidFile = join(home, 'server.pid')
+    writeFileSync(pidFile, '999999999\n')
+
+    try {
+      const { stopDaemon } = await loadCli()
+      stopDaemon()
+
+      expect(existsSync(pidFile)).toBe(false)
+    } finally {
+      rmSync(home, { recursive: true, force: true })
+    }
+  })
+
   it('resets an existing admin user to the default password', async () => {
     const home = mkdtempSync(join(tmpdir(), 'hermes-web-ui-cli-default-login-'))
     process.env.HERMES_WEB_UI_HOME = home