[#40] fix: return server capabilities at GET / and add GET /version-info

  - GET / now returns server capabilities and entry points per REQ_INTEROP_010
    (name, version, endpoints list, capabilities object)
  - Add GET /version-info for version information per REQ_INTEROP_001
    (status, version, timestamp)
  - Update test_01_root_endpoint to verify capabilities response
  - Add test_01b_version_info_endpoint for new endpoint
  - Update Postman collection with new requests

Author: Michał Fąferek

postman/collections/ros2-medkit-gateway.postman_collection.json

@@ -9,7 +9,7 @@
       "name": "Discovery",
       "item": [
         {
-          "name": "GET Gateway Info",
+          "name": "GET Server Capabilities",
           "request": {
             "method": "GET",
             "header": [],
@@ -22,7 +22,25 @@
                 ""
               ]
             },
-            "description": "Get gateway status and version information"
+            "description": "Get server capabilities and entry points (REQ_INTEROP_010). Returns server name, version, available endpoints, and capabilities."
+          },
+          "response": []
+        },
+        {
+          "name": "GET Version Info",
+          "request": {
+            "method": "GET",
+            "header": [],
+            "url": {
+              "raw": "{{base_url}}/version-info",
+              "host": [
+                "{{base_url}}"
+              ],
+              "path": [
+                "version-info"
+              ]
+            },
+            "description": "Get gateway status and version information (REQ_INTEROP_001). Returns status, version, and timestamp."
           },
           "response": []
         },

src/ros2_medkit_gateway/include/ros2_medkit_gateway/rest_server.hpp

@@ -40,6 +40,7 @@ class RESTServer {
     // Route handlers
     void handle_health(const httplib::Request& req, httplib::Response& res);
     void handle_root(const httplib::Request& req, httplib::Response& res);
+    void handle_version_info(const httplib::Request& req, httplib::Response& res);
     void handle_list_areas(const httplib::Request& req, httplib::Response& res);
     void handle_list_components(const httplib::Request& req, httplib::Response& res);
     void handle_area_components(const httplib::Request& req, httplib::Response& res);

src/ros2_medkit_gateway/src/rest_server.cpp

@@ -44,11 +44,16 @@ void RESTServer::setup_routes() {
         handle_health(req, res);
     });
 
-    // Root
+    // Root - server capabilities and entry points (REQ_INTEROP_010)
     server_->Get("/", [this](const httplib::Request& req, httplib::Response& res) {
         handle_root(req, res);
     });
 
+    // Version info (REQ_INTEROP_001)
+    server_->Get("/version-info", [this](const httplib::Request& req, httplib::Response& res) {
+        handle_version_info(req, res);
+    });
+
     // Areas
     server_->Get("/areas", [this](const httplib::Request& req, httplib::Response& res) {
         handle_list_areas(req, res);
@@ -160,6 +165,39 @@ void RESTServer::handle_health(const httplib::Request& req, httplib::Response& r
 void RESTServer::handle_root(const httplib::Request& req, httplib::Response& res) {
     (void)req;  // Unused parameter
 
+    try {
+        json response = {
+            {"name", "ROS 2 Medkit Gateway"},
+            {"version", "0.1.0"},
+            {"endpoints", json::array({
+                "/health",
+                "/version-info",
+                "/areas",
+                "/components",
+                "/areas/{area_id}/components",
+                "/components/{component_id}/data",
+                "/components/{component_id}/data/{topic_name}"
+            })},
+            {"capabilities", {
+                {"discovery", true},
+                {"data_access", true}
+            }}
+        };
+
+        res.set_content(response.dump(2), "application/json");
+    } catch (const std::exception& e) {
+        res.status = StatusCode::InternalServerError_500;
+        res.set_content(
+            json{{"error", "Internal server error"}}.dump(),
+            "application/json"
+        );
+        RCLCPP_ERROR(rclcpp::get_logger("rest_server"), "Error in handle_root: %s", e.what());
+    }
+}
+
+void RESTServer::handle_version_info(const httplib::Request& req, httplib::Response& res) {
+    (void)req;  // Unused parameter
+
     try {
         json response = {
             {"status", "ROS 2 Medkit Gateway running"},
@@ -174,7 +212,11 @@ void RESTServer::handle_root(const httplib::Request& req, httplib::Response& res
             json{{"error", "Internal server error"}}.dump(),
             "application/json"
         );
-        RCLCPP_ERROR(rclcpp::get_logger("rest_server"), "Error in handle_root: %s", e.what());
+        RCLCPP_ERROR(
+            rclcpp::get_logger("rest_server"),
+            "Error in handle_version_info: %s",
+            e.what()
+        );
     }
 }
 

src/ros2_medkit_gateway/test/test_integration.test.py

@@ -167,16 +167,47 @@ def _get_json(self, endpoint: str):
 
     def test_01_root_endpoint(self):
         """
-        Test GET / returns gateway status and version.
+        Test GET / returns server capabilities and entry points.
 
         @verifies REQ_INTEROP_010
         """
         data = self._get_json('/')
+        self.assertIn('name', data)
+        self.assertIn('version', data)
+        self.assertIn('endpoints', data)
+        self.assertIn('capabilities', data)
+
+        self.assertEqual(data['name'], 'ROS 2 Medkit Gateway')
+        self.assertEqual(data['version'], '0.1.0')
+
+        # Verify endpoints list
+        self.assertIsInstance(data['endpoints'], list)
+        self.assertIn('/health', data['endpoints'])
+        self.assertIn('/version-info', data['endpoints'])
+        self.assertIn('/areas', data['endpoints'])
+        self.assertIn('/components', data['endpoints'])
+
+        # Verify capabilities
+        self.assertIn('discovery', data['capabilities'])
+        self.assertIn('data_access', data['capabilities'])
+        self.assertTrue(data['capabilities']['discovery'])
+        self.assertTrue(data['capabilities']['data_access'])
+        print('✓ Root endpoint test passed')
+
+    def test_01b_version_info_endpoint(self):
+        """
+        Test GET /version-info returns gateway status and version.
+
+        @verifies REQ_INTEROP_001
+        """
+        data = self._get_json('/version-info')
         self.assertIn('status', data)
         self.assertIn('version', data)
+        self.assertIn('timestamp', data)
         self.assertEqual(data['status'], 'ROS 2 Medkit Gateway running')
         self.assertEqual(data['version'], '0.1.0')
-        print('✓ Root endpoint test passed')
+        self.assertIsInstance(data['timestamp'], int)
+        print('✓ Version info endpoint test passed')
 
     def test_02_list_areas(self):
         """