fix: add /api/healthz alias for gateway proxy health check

Gateway proxies /api/neko/healthz → /api/healthz on the agent,
but healthz was only on /healthz. Dashboard status bar showed
permanent Offline.

小橘 🍊（NEKO Team）

packages/cli-workflow/src/commands/serve/app.ts

@@ -38,6 +38,7 @@ export function createApp(storageRoot: string): Hono {
   });
 
   app.get("/healthz", (c) => c.json({ ok: true }));
+  app.get("/api/healthz", (c) => c.json({ ok: true }));
 
   app.route("/api/workflows", createWorkflowRoutes(storageRoot));
   app.route("/api/threads", createThreadRoutes(storageRoot));