Expand README for src/article-api (#58897)

Author: heiskr

src/article-api/README.md

@@ -168,3 +168,42 @@ A list of pages available for a fully qualified path containing the target langu
 
 ---
 
+
+## Local Development
+
+### Bootstrap steps
+
+1. Start the dev server:
+   ```bash
+   npm run dev
+   ```
+
+2. Test API endpoints locally:
+   ```bash
+   curl http://localhost:4000/api/article/meta?pathname=/en/get-started
+   curl http://localhost:4000/api/article/body?pathname=/en/get-started
+   curl http://localhost:4000/api/pagelist/en/free-pro-team@latest
+   ```
+
+### Running tests
+
+```bash
+npm run test -- src/article-api/tests
+```
+
+## Ownership
+
+- Team: Docs Engineering
+
+## Transformers
+
+Currently implemented transformers:
+- **REST API transformer** (`rest-transformer.ts`) - Converts REST API autogenerated content
+- **GraphQL transformer** (`graphql-transformer.ts`) - Converts GraphQL API autogenerated content
+- **Audit logs transformer** (`audit-logs-transformer.ts`) - Converts audit log tables to markdown
+
+### Known limitations
+- Some autogenerated content types don't have transformers yet
+- Cache invalidation is manual
+- No built-in rate limiting
+- Limited API versioning