feat(health): probe + classify engine on a 60s cron

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/health/checker.test.js

@@ -0,0 +1,19 @@
+import { describe, it, expect, vi } from 'vitest';
+import { classify, checkAll } from '../../lib/health/checker.js';
+
+describe('health classify', () => {
+  it('ok when reachable and fast', () => expect(classify({ ok: true, latency: 120 }).status).toBe('ok'));
+  it('warn when reachable but slow', () => expect(classify({ ok: true, latency: 4000 }).status).toBe('warn'));
+  it('warn on non-2xx/3xx reachable', () => expect(classify({ ok: false, reachable: true, latency: 50 }).status).toBe('warn'));
+  it('down when unreachable', () => expect(classify({ ok: false, reachable: false, error: 'ECONN' }).status).toBe('down'));
+});
+
+describe('checkAll', () => {
+  it('probes each service and returns a status per id', async () => {
+    const probe = vi.fn().mockResolvedValue({ ok: true, latency: 30 });
+    const svcs = [{ id: 'a', url: 'http://x' }, { id: 'b', url: 'http://y' }];
+    const out = await checkAll(svcs, probe);
+    expect(out.map(o => o.service_id).sort()).toEqual(['a', 'b']);
+    expect(out.every(o => o.status === 'ok')).toBe(true);
+  });
+});