[WIP] Add OJ system based on API documentation

[Copilot]

• Analyze API documentation and understand requirements
• Set up Vue.js/React project with proper structure
• Create API service layer with axios for API calls
• Implement Problem module (list, detail pages)
• Implement Submission module with polling mechanism
• Implement Language module
• Add UI components and styling
• Test and verify the implementation

Original prompt

根据该md提供的接口，编写oj系统
注意：查询提交结果采用轮询

The user has attached the following file paths as relevant context:

• oj-frontend-api-documentation.md

用户已从其工作区附加以下文件:

• oj-frontend-api-documentation.md

Created from VS Code via the GitHub Pull Request extension.

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