Update npm dependencies and fix OpenAPI lint errors

- Upgrade @openapitools/openapi-generator-cli to v2.20.2
- Upgrade @stoplight/prism-cli to v5.14.2
- Upgrade @stoplight/spectral-cli to v6.15.0
- Upgrade prettier to v3.5.3
- Change OpenAPI version from 3.1.0 to 3.0.3 to resolve validation errors

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: t2h5

package.json

@@ -18,12 +18,12 @@
     "mock": "prism mock -d -p 13000 ./generated/openapi.json"
   },
   "devDependencies": {
-    "@openapitools/openapi-generator-cli": "^2.13.4",
-    "@stoplight/prism-cli": "^5.7.0",
-    "@stoplight/spectral-cli": "^6.11.1",
+    "@openapitools/openapi-generator-cli": "^2.20.2",
+    "@stoplight/prism-cli": "^5.14.2",
+    "@stoplight/spectral-cli": "^6.15.0",
     "chokidar-cli": "^3.0.0",
     "npm-run-all": "^4.1.5",
-    "prettier": "^3.2.5",
+    "prettier": "^3.5.3",
     "rimraf": "^6.0.1"
   }
 }

root.yml

@@ -1,4 +1,4 @@
-openapi: 3.1.0
+openapi: 3.0.3
 
 info:
   title: Structured OpenAPI Schema
@@ -19,7 +19,7 @@ tags:
     description: tag for user
 
 paths:
-  /users:
+  '/users':
     $ref: ./paths/users.yml
-  /users/{user_id}:
+  '/users/{user_id}':
     $ref: ./paths/users-by-id.yml