Add workflow to auto-merge Dependabot PRs

Enables GitHub auto-merge on Dependabot PRs so they merge
automatically once CI checks pass, reducing manual maintenance.

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

Author: Guillermo Moraleda

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

@@ -0,0 +1,18 @@
+name: Auto-merge Dependabot PRs
+
+on: pull_request
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  auto-merge:
+    runs-on: ubuntu-latest
+    if: github.actor == 'dependabot[bot]'
+    steps:
+      - name: Enable auto-merge
+        run: gh pr merge --auto --merge "$PR_URL"
+        env:
+          PR_URL: ${{ github.event.pull_request.html_url }}
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}