revert(ci): use peter-evans/create-pull-request for refresh PR

Reverts the gh + native git workflow back to peter-evans/create-pull-request@v6.
The append-commits design was tempting but the single-squash-commit model that
peter-evans provides is the better fit here:

- When the responses are unchanged across runs, peter-evans diffs tree (not
  commit SHA), so identical content -> no push, no PR churn. The branch sits
  untouched even though the locally computed commit would have a fresh
  timestamp.
- When the responses change, the branch is force-pushed with a new single
  commit. The diff against main always reflects the latest API state in one
  reviewable chunk, instead of accumulating a growing chain of incremental
  refresh commits.
- When the responses match main (typically after the PR has been merged),
  peter-evans automatically closes the PR and deletes the branch.

Kept from the previous iteration: the concurrency group so cron and manual
workflow_dispatch runs cannot race, and the comment documenting the manual
trigger.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: Daniel Jones

.github/workflows/refresh-v3-languages.yml

@@ -15,96 +15,36 @@ concurrency:
   group: refresh-v3-languages
   cancel-in-progress: false
 
-env:
-  REFRESH_BRANCH: chore/refresh-v3-languages
-  COMMIT_PATHS: data/v3-languages
-
 jobs:
   refresh:
-    name: Fetch and update refresh PR
+    name: Fetch and open PR on diff
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout main
+      - name: Checkout
         uses: actions/checkout@v5
-        with:
-          fetch-depth: 0
-
-      - name: Detect existing refresh PR
-        id: pr
-        env:
-          GH_TOKEN: ${{ github.token }}
-        run: |
-          number=$(gh pr list \
-            --base main \
-            --head "$REFRESH_BRANCH" \
-            --state open \
-            --json number \
-            --jq '.[0].number // ""')
-          echo "number=$number" >> "$GITHUB_OUTPUT"
-          if [ -n "$number" ]; then
-            echo "Existing refresh PR: #$number"
-          else
-            echo "No existing refresh PR"
-          fi
-
-      - name: Check out existing refresh branch
-        if: steps.pr.outputs.number != ''
-        run: |
-          git fetch origin "$REFRESH_BRANCH"
-          git checkout -B "$REFRESH_BRANCH" "origin/$REFRESH_BRANCH"
 
       - name: Fetch latest /v3/languages responses
         env:
           DEEPL_AUTH_KEY: ${{ secrets.DEEPL_API_KEY }}
         run: python3 scripts/fetch_v3_languages.py
 
-      - name: Detect content changes
-        id: diff
-        run: |
-          if git diff --quiet -- $COMMIT_PATHS; then
-            echo "changed=false" >> "$GITHUB_OUTPUT"
-            echo "No changes in $COMMIT_PATHS; nothing to commit."
-          else
-            echo "changed=true" >> "$GITHUB_OUTPUT"
-          fi
-
-      - name: Configure git author
-        if: steps.diff.outputs.changed == 'true'
-        run: |
-          git config user.name "github-actions[bot]"
-          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
-
-      - name: Append commit to existing refresh PR
-        if: steps.diff.outputs.changed == 'true' && steps.pr.outputs.number != ''
-        env:
-          RUN_URL: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
-        run: |
-          git add -- $COMMIT_PATHS
-          git commit -m "chore(v3-languages): refresh vended responses
-
-          Run: $RUN_URL"
-          git push origin "$REFRESH_BRANCH"
-
-      - name: Create new refresh PR
-        if: steps.diff.outputs.changed == 'true' && steps.pr.outputs.number == ''
-        env:
-          GH_TOKEN: ${{ github.token }}
-          RUN_URL: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
-        run: |
-          git checkout -b "$REFRESH_BRANCH"
-          git add -- $COMMIT_PATHS
-          git commit -m "chore(v3-languages): refresh vended responses
-
-          Run: $RUN_URL"
-          git push -u origin "$REFRESH_BRANCH"
-          gh pr create \
-            --base main \
-            --head "$REFRESH_BRANCH" \
-            --title "chore(v3-languages): refresh vended responses" \
-            --body "Automated refresh of \`data/v3-languages/\` from \`https://api.deepl.com/v3/languages\`, opened by the \`refresh-v3-languages\` workflow.
-
-          Subsequent runs append new commits to this PR when the responses change again, so the diff against \`main\` represents the cumulative update. Review the latest state and merge when ready.
-
-          First run: $RUN_URL" \
-            --label automated \
-            --label v3-languages
+      - name: Open or update refresh PR
+        uses: peter-evans/create-pull-request@v6
+        with:
+          branch: chore/refresh-v3-languages
+          base: main
+          commit-message: "chore(v3-languages): refresh vended responses"
+          title: "chore(v3-languages): refresh vended responses"
+          body: |
+            Automated refresh of `data/v3-languages/` from `https://api.deepl.com/v3/languages`,
+            opened by the `refresh-v3-languages` workflow.
+
+            This PR is rewritten in place on each run: if the vended responses change again
+            before merge, the branch is force-pushed with a new single squashed commit so the
+            diff against `main` always reflects the latest API state. If a run finds the
+            responses identical to what is already on the branch, the branch is left untouched.
+            If a run finds the responses match `main` (e.g. the PR was merged), this PR is
+            closed and the branch deleted automatically.
+          add-paths: data/v3-languages/**
+          delete-branch: true
+          labels: automated, v3-languages