feat: v0.5.0 — machine-readable API docs: GET /api/version + OpenAPI 3.1 spec at /api/openapi; AGENTS.md points agents at the live spec

app/api/openapi/route.ts

@@ -0,0 +1,5 @@
+import { openApiSpec } from '@/lib/openapi';
+
+export async function GET() {
+  return Response.json(openApiSpec);
+}