feat: add in-memory caching for GitHub API responses

[paanipoorie]

Summary

Adds short-term in-memory caching for GitHub API responses to reduce redundant API calls and improve performance.

Changes

• Added cache utility (lib/cache.ts)
• Integrated caching into GitHub fetch logic
• TTL set to 5–10 minutes
• Added support for refresh=true to bypass cache

Behavior

• Same username within TTL returns cached data
• Reduces repeated GitHub API calls
• refresh=true forces fresh fetch

Test

• Ran npm run format, npm run lint, and npm run test
• Verified cache hit/miss behavior locally

Fixes #46

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Project	Deployment	Actions	Updated (UTC)
commitpulse	Ready	Preview, Comment	May 1, 2026 10:41pm

[paanipoorie]

Implemented caching with TTL and refresh bypass.

All checks are passing (format, lint, tests).
Ready for review.

[JhaSourav07]

@paanipoorie

Its fine i am merging this PR.