feat: add daemon server skeleton with health check endpoint

packages/daemon/src/__tests__/health.test.ts

@@ -0,0 +1,23 @@
+import { describe, it, expect, beforeAll, afterAll } from 'vitest';
+import http from 'node:http';
+import { startServer } from '../server.js';
+
+describe('daemon health endpoint', () => {
+  let server: http.Server;
+  const port = 19528;
+
+  beforeAll(async () => {
+    server = await startServer(port);
+  });
+
+  afterAll(async () => {
+    await new Promise<void>((resolve) => server.close(() => resolve()));
+  });
+
+  it('GET /health returns 200 with status ok', async () => {
+    const response = await fetch(`http://127.0.0.1:${port}/health`);
+    expect(response.status).toBe(200);
+    const json = await response.json();
+    expect(json).toEqual({ status: 'ok' });
+  });
+});

packages/daemon/src/routes/health.ts

@@ -0,0 +1,11 @@
+import type { IncomingMessage, ServerResponse } from 'node:http';
+
+export function healthRoute(req: IncomingMessage, res: ServerResponse): boolean {
+  const url = new URL(req.url || '/', 'http://localhost');
+  if (req.method === 'GET' && url.pathname === '/health') {
+    res.writeHead(200, { 'Content-Type': 'application/json' });
+    res.end(JSON.stringify({ status: 'ok' }));
+    return true;
+  }
+  return false;
+}

packages/daemon/src/server.ts

@@ -0,0 +1,25 @@
+import http from 'node:http';
+import { healthRoute } from './routes/health.js';
+
+const routes = [healthRoute];
+
+export function startServer(port: number): Promise<http.Server> {
+  return new Promise((resolve) => {
+    const server = http.createServer((req, res) => {
+      for (const route of routes) {
+        if (route(req, res)) return;
+      }
+      res.writeHead(404, { 'Content-Type': 'application/json' });
+      res.end(JSON.stringify({ ok: false, error: { code: 'INTERNAL', message: 'not found' } }));
+    });
+
+    server.listen(port, '127.0.0.1', () => {
+      console.log(`[daemon] VisionL daemon started on http://127.0.0.1:${port}`);
+      resolve(server);
+    });
+  });
+}
+
+// Direct start when running as script
+const port = parseInt(process.env.VISIONL_PORT || '9527', 10);
+startServer(port);