chore: add dependabot config and auto-merge workflow

Author: Roland Groza

.github/dependabot.yml

@@ -0,0 +1,24 @@
+version: 2
+
+updates:
+  - package-ecosystem: npm
+    directory: /
+    rebase-strategy: auto
+    schedule:
+      interval: "weekly"
+    commit-message:
+      prefix: "chore(deps):"
+    versioning-strategy: increase
+    # Patch bumps grouped into one PR (auto-merged on green CI); minor bumps
+    # grouped into a separate PR for manual review; majors open individually.
+    groups:
+      patch:
+        patterns:
+          - "*"
+        update-types:
+          - patch
+      minor:
+        patterns:
+          - "*"
+        update-types:
+          - minor

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

@@ -0,0 +1,25 @@
+name: Dependabot auto-merge
+on: pull_request
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  auto-merge:
+    if: ${{ github.actor == 'dependabot[bot]' }}
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Fetch update metadata
+        id: meta
+        uses: dependabot/fetch-metadata@v2
+
+      # Auto-merge patch updates once the required checks pass. Minor and major
+      # updates are left for manual review (the `if` below excludes them).
+      - name: Enable auto-merge for patch
+        if: ${{ steps.meta.outputs.update-type == 'version-update:semver-patch' }}
+        run: gh pr merge --auto --squash "$PR_URL"
+        env:
+          PR_URL: ${{ github.event.pull_request.html_url }}
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}