feat(openapi): add /healthy route for health check

Server/openapi.json

@@ -546,6 +546,44 @@
           }
         }
       }
+    },
+    "/healthy": {
+      "get": {
+        "tags": ["healthy"],
+        "description": "Health check",
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "properties": {
+                    "message": {
+                      "type": "string"
+                    }
+                  }
+                }
+              }
+            }
+          },
+          "500": {
+            "description": "Internal Server Error",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "properties": {
+                    "message": {
+                      "type": "string"
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
     }
   },
   "components": {