feat: implement issue recommendation system for contributor progression

[parvninama]

Changes:

Issue recommendation workflow on PR merge

• Triggers recommendation system when a PR is merged
• Ensures only valid contributor PRs are processed (non-bot, merged PRs)

Linked issue resolution

• Added resolveLinkedIssue helper using closingIssuesReferences (GraphQL)
• Uses the linked issue as the source of truth for labels
• Skips recommendation if no linked issue is found

Difficulty-based progression system

• Introduced SKILL_HIERARCHY:
  • good first issue → beginner → intermediate → advanced
• Determines completed issue level from labels
• Recommends issues using progression:
  • next level (primary)
  • same level (fallback)
  • lower level (final fallback, except Beginner → GFI)

Issue filtering and discovery

• Fetches issues using GitHub Search API
• Filters:
  • open issues only
  • unassigned issues
  • matching difficulty label
  • ready for dev label required
• Limits results to a small, relevant set (top 5)

Error handling and resilience

• Introduced safeFetchIssues wrapper
• Differentiates:
  • [] → no issues found
  • null → API failure
• Posts a single error comment tagging maintainers on failure
• Prevents duplicate error comments

Recommendation comment system

• Builds structured, readable comment with clickable issue links
• Mentions contributor directly
• Silent exit when no recommendations are available (avoids noise)

Code structure improvements

• Extracted linked issue resolution into reusable helper (resolveLinkedIssue)
• Kept API logic centralized in helpers
• Maintained separation between:
  • command logic (recommendation)
  • API utilities
  • workflow entry point

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Testing:

• In progress

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Linked Issue:

• Fixes [Intermediate]: Issue recommendation system for contributor progression #1261