fix UserType enum mapping and implement unified API response

- Fix UserType enum mapping issue by adding fromValue method and custom type handler
- Create unified API response structure with ErrorCode constants
- Update AuthController to use standardized response format with proper error codes
- Add verification code authentication system replacing password-based auth
- Improve Swagger documentation with detailed API annotations

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

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

.claude/settings.local.json

@@ -7,7 +7,9 @@
       "Bash(mvn:*)",
       "Bash(./mvnw clean compile)",
       "Bash(cd:*)",
-      "Bash(ls:*)"
+      "Bash(ls:*)",
+      "Bash(find:*)",
+      "Bash(git add:*)"
     ],
     "deny": []
   }