[FEAT repo-guard] - Integrate GitHub API Rate Limit Awareness

[onuryilmaz]

[FEAT repo-guard] - Integrate GitHub API Rate Limit Awareness

Description

The current implementation in internal/github uses a standard client without explicit rate limit handling. Implement a custom http.RoundTripper or use a library that respects GitHub's X-RateLimit-Reset headers and implements exponential backoff.

Labels

• feature
• github-api
• reliability

User Story

As a Developer I can ensure the operator doesn't fail due to GitHub rate limiting, so that sync operations remain robust during high-load.

Benefit

Prevents the operator from being throttled by GitHub during large sync operations or when managing many organizations.

Acceptance Criteria

• GitHub client is updated to handle rate limits.
• Custom http.RoundTripper or library is integrated.
• X-RateLimit-Reset headers are respected.
• Exponential backoff is implemented.
• Unit tests simulate rate limiting and verify backoff behavior.