Add auto-merge workflow for Dependabot PRs

Auto-approves and enables squash merge for Dependabot PRs.
Requires branch protection on main with required status checks
and "Allow auto-merge" enabled in repo settings.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ksroda-sa

.github/workflows/dependabot-auto-merge.yml

@@ -0,0 +1,23 @@
+name: Dependabot auto-merge
+
+on: pull_request
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  auto-merge:
+    runs-on: ubuntu-latest
+    if: github.actor == 'dependabot[bot]'
+    steps:
+      - name: Approve PR
+        run: gh pr review --approve "$PR_URL"
+        env:
+          PR_URL: ${{ github.event.pull_request.html_url }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Enable auto-merge
+        run: gh pr merge --auto --squash "$PR_URL"
+        env:
+          PR_URL: ${{ github.event.pull_request.html_url }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}