Add /api/admin/maintenance/banner endpoint

[greatest0fallt1me]

Description

This is a backend issue for the GrantFox campaign. This is a backend issue for the GrantFox campaign. Admin endpoint to set a maintenance banner.

Requirements and Context

• Implement per the description
• Add focused tests for the change
• Document any API/visible changes
• Adhere to repo's lint and code style
• Must be secure, tested, and documented
• Should be efficient and easy to review

Suggested Execution

1. Fork the repo and create a branch

   git checkout -b feature/maintenance-banner

2. Implement changes
   • src/routes/admin/maintenance/banner.ts (new)
3. Test and commit
   • Run the repo's standard test suite and lint
   • Cover edge cases; include output in the PR

Example commit message

feat: admin maintenance banner

Acceptance Criteria

• Implementation matches the description
• Tests added and passing
• Code review approved
• Docs updated

Guidelines

• Minimum 90% test coverage on changed lines
• Input validation at the boundary; standardized error envelope
• Structured logging with correlation IDs
• Clear documentation and inline comments
• Timeframe: 96 hours

[gloskull]

Hi, I’d love to work on this issue. I have 4 years of experience across backend, frontend, full-stack, and smart contract development. I understand the task clearly and can deliver a clean, efficient, well-tested solution on time, with strong focus on code quality and maintainability. My PR will be submitted in under 10 hours.

[DANeiraGarcia]

Hi team! I would love to work on this issue. I have experience building secure API routes in TypeScript and writing focused tests for endpoint validation. I'll make sure to deliver a clean implementation for the maintenance banner route according to the guidelines. Please assign it to me!