Add OpenAPI/Swagger documentation for server integration

Updated server integration guide and CLI README to document automatic OpenAPI 3.0 spec generation and access URLs. This helps users import API definitions into Swagger UI, Postman, and similar tools for easier visualization and testing.

Author: hotlong

docs/guide/server-integration.md

@@ -73,6 +73,21 @@ interface ObjectQLRequest {
 }
 ```
 
+## 📖 OpenAPI / Swagger Support
+
+`@objectql/server` automatically generates an OpenAPI 3.0 specification from your registered schema.
+
+You can access the spec by appending `/openapi.json` to your handler's mount path.
+
+**Example URLs:**
+*   **CLI Serve:** `http://localhost:3000/openapi.json`
+*   **Express (mounted at /api/objectql):** `http://localhost:3000/api/objectql/openapi.json`
+*   **Next.js (pages/api/objectql.ts):** `http://localhost:3000/api/objectql/openapi.json`
+
+This JSON file describes your data objects as "Virtual REST" endpoints (`GET /user`, `POST /user`, etc.), allowing you to easily import them into **Swagger UI**, **Postman**, or other API tools for visualization and testing.
+
+## Example Usage
+
 **Example (cURL):**
 
 ```bash

packages/cli/README.md

@@ -32,6 +32,10 @@ objectql serve
 objectql serve --dir ./src/schema --port 8080
 ```
 
+The server exposes:
+*   **JSON API Endpoint**: `http://localhost:<port>/` (POST)
+*   **OpenAPI Spec**: `http://localhost:<port>/openapi.json` (GET) - Import this into Postman or Swagger UI.
+
 ### `repl` (alias: `r`)
 
 Start an interactive shell to query your data.