feat(my-prs): add Needs Changes tab and mentor feedback display

[Tirthpanchori]

Summary

Adds a NEEDS CHANGES tab to /my-prs, with a matching status badge, action
button, and inline mentor-feedback text, so contributors can see when a mentor
has requested changes on an open PR — previously this state had no visibility
on this page at all.

Type of Change

• Bug fix
• New feature
• UI / UX improvement
• Refactor
• Documentation
• Other

Related Issue

Closes #677

What was changed?

• Added changes_requested + review_feedback to the EnrichedPR type (page.tsx, pr-list.tsx)
• page.tsx: query pull_request_pipeline_stages + pull_request_reviews.body_excerpt, layer on top of the existing recommendations/help_requests logic as a higher-priority signal (fresher, comes from GitHub review webhooks directly)
• pr-list.tsx: new NEEDS CHANGES tab/filter/count, new badge + action button states, inline feedback quote block
• Existing mentor_status logic untouched — added to, not replaced, per maintainer guidance to keep this a single PR with no backend changes

Known limitation (not fixed here): recommendations/help_requests and pipeline_stages aren't cross-written anywhere in the codebase, so these two review-status signals can theoretically drift. Flagging for visibility, not expanding scope here.

Also noticed, not touched: PRMeta double-renders +{xp_earned} XP earned for merged PRs with XP set — pre-existing, unrelated bug.

Screenshots

Checklist

• My code follows the project structure and conventions
• I tested this locally (npm run dev)
• No hardcoded secrets or credentials
• I have updated documentation if needed

[vercel]

@Tirthpanchori is attempting to deploy a commit to the codersogs-3057's projects Team on Vercel.

A member of the Team first needs to authorize it.

[pavsoss]

The implementation LGTM, just one edge case bug:
the Needs Changes filter/count needs the same state === 'open' guard as pending_review, otherwise the drift the author flagged leaks stale merged/closed PRs into the tab

[Tirthpanchori]

Good catch - fixed in the latest commit. Added the same state === 'open' guard to the needs_changes filter and count that pending_review already had. getPRStatusInfo itself was already safe (checks merged/closed before
changes_requested), so this was isolated to the tab filter/count logic in PRList.

[jakharmonika364]

LGTM, thanks!