fix: show rate limit error with reset time in CI Analytics (#244)

[mallya-m]

Summary

Closes #244

Fixes the CI Analytics refresh button silently failing when GitHub API is rate-limited (403). Users now see a clear yellow warning with the exact reset time, and the button is disabled until the rate limit resets automatically.

Type of Change

• Bug fix
• New feature
• Documentation update
• Refactor / code cleanup

Changes Made

• Check for res.status === 403 before generic error handling in CIAnalytics.tsx
• Parse X-RateLimit-Reset header and convert Unix timestamp to local HH:MM using toLocaleTimeString()
• Show yellow-tinted error box: "GitHub API rate limit reached. Resets at HH:MM. Try again later."
• Disable Refresh button with label "Retry at HH:MM" while rate limited
• Auto-clears error and re-enables button via setTimeout when reset time passes
• No new dependencies added

How to Test

1. Run npm run dev
2. Open the CI Analytics card on the dashboard
3. To simulate 403: temporarily return 403 from the API route with an X-RateLimit-Reset header
4. Verify yellow warning appears with reset time
5. Verify button is disabled and shows "Retry at HH:MM"
6. After reset time passes, verify button re-enables automatically

Checklist

• Linked issue in summary
• npm run lint passes locally
• No TypeScript errors (npm run type-check)
• Self-reviewed the diff
• Added/updated tests if applicable

[vercel]

@mallya-m is attempting to deploy a commit to the PRIYANSHU DOSHI's projects Team on Vercel.

A member of the Team first needs to authorize it.

[github-actions]

GSSoC Label Checklist 🏷️

@Priyanshu-byte-coder — please apply the appropriate labels before merging:

Difficulty (pick one):

• level:beginner — 20 pts
• level:intermediate — 35 pts
• level:advanced — 55 pts
• level:critical — 80 pts

Quality (optional):

• quality:clean — ×1.2 multiplier
• quality:exceptional — ×1.5 multiplier

Validation (required to score):

• gssoc:approved — counts for points
• gssoc:invalid / gssoc:spam / gssoc:ai-slop — does not score

Type labels (type:*) are auto-detected from files and title. Review and adjust if needed.
Points formula: (difficulty × quality_multiplier) + type_bonus

[mallya-m]

Hi @Priyanshu-byte-coder!

PR is ready for review. Here's what was fixed:

• Detects 403 rate-limit responses separately from other errors
• Reads X-RateLimit-Reset header and converts to local HH:MM time
• Shows a yellow warning instead of silent failure
• Disables the Refresh button with label "Retry at HH:MM" until reset passes
• Auto-re-enables the button via setTimeout — no manual refresh needed

Could you please add:

• gssoc:approved
• level:intermediate
• quality:clean
• type:bug
• type:devops

Thanks!