Add PR triage workflow

[Kyle-Ye]

Add automated PR triage workflow that uses Claude AI to automatically analyze and label pull requests.

This workflow:

• Triggers when new PRs are opened
• Uses the shared pr-triage workflow from OpenSwiftUIProject/github-workflows
• Automatically applies appropriate labels based on PR content
• Inherits necessary secrets for authentication

Follows the same pattern as the existing issue-triage workflow.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 4.81%. Comparing base (78b74c6) to head (13fe72f).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #192   +/-   ##
=====================================
  Coverage   4.81%   4.81%           
=====================================
  Files         28      28           
  Lines        831     831           
=====================================
  Hits          40      40           
  Misses       791     791           

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🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.