chore: move postman guide into postman folder as README.md

- docs/postman-guide.md → docs/postman/README.md (auto-loads on folder view)
- Updated main README.md links

README.md

@@ -91,9 +91,9 @@ curl -H "Authorization: Bearer YOUR_TOKEN" http://localhost:8080/api/health
 
 Postman collection, environment, and a full usage guide are provided under [`docs/postman/`](docs/postman/):
 
-- [`docs/postman/collection.json`](docs/postman/collection.json) - Complete API collection with all 12 endpoints
-- [`docs/postman/environment.json`](docs/postman/environment.json) - Environment variables (base URL, token)
-- [`docs/postman-guide.md`](docs/postman-guide.md) - Setup, examples, and troubleshooting
+- [`docs/postman/collection.json`](docs/postman/collection.json) — Complete API collection with all 12 endpoints
+- [`docs/postman/environment.json`](docs/postman/environment.json) — Environment variables (base URL, token)
+- [`docs/postman/README.md`](docs/postman/README.md) — Setup, examples, and troubleshooting
 
 A bulk user creation example is at [`docs/examples/bulk-request.json`](docs/examples/bulk-request.json).
 
@@ -105,7 +105,7 @@ A bulk user creation example is at [`docs/examples/bulk-request.json`](docs/exam
 - `src/` - Go source code (cmd/server, internal packages, migrations)
 - `docs/` - Documentation, OpenAPI spec, Postman files, and usage examples
   - `docs/openapi.yml` - OpenAPI 3.0.3 specification for all endpoints
-  - `docs/postman-guide.md` - Postman setup and usage guide
+  - `docs/postman/README.md` - Postman setup and usage guide
   - `docs/postman/` - Postman collection and environment files
   - `docs/examples/` - Example request payloads
 - `install-authelia-api.sh` - Bare-metal installation script