fix: handle detached HEAD in PR workflows

[danielsuguimoto]

Ticket

SKIPPED

Summary

Fixes a failure in pr/review and pr/fix commands when run inside GitHub Actions CI/CD pipelines. By default, actions/checkout@v4 on pull_request events checks out the PR merge commit in detached HEAD mode — meaning git branch --show-current returns empty. The branch alignment logic previously treated any mismatch as a checkout target, but without the branch being fetched locally the checkout would fail and the command would stop.

Root Cause

GitHub Actions pull_request workflows run on a detached HEAD pointing to the synthetic merge commit (refs/pull/N/merge), not the PR head branch. The old logic compared <current-branch> against <pr-branch> and immediately tried git checkout <pr-branch> on mismatch — which fails because the branch ref is not available locally in a shallow CI clone.

Changes

• Added git rev-parse HEAD → <current-head> to the load-pr component to capture the current commit SHA alongside the branch name
• Rewrote branch alignment in pr/review and pr/fix from a two-way to a three-way check:
  1. <current-branch> equals <pr-branch> → already on the correct branch, proceed
  2. <current-branch> is empty (detached HEAD) and <current-head> matches pr.headRefOid → already at the correct commit, skip checkout
  3. Otherwise → run git fetch origin <pr-branch> first to ensure the branch is available locally, then checkout
• The explicit fetch before checkout makes the commands self-sufficient regardless of how shallow the CI clone is, removing the dependency on ref: ${{ github.head_ref }} in the caller's workflow
• Added ref: ${{ github.head_ref }} to the checkout step in the Kompass CI workflow so the runner checks out the named branch directly, avoiding detached HEAD entirely and hitting the fast path in the alignment logic