adds(workflow): auto tags

.github/workflows/auto-tags.yml

@@ -0,0 +1,112 @@
+name: Auto tag from PR labels
+
+on:
+  pull_request:
+    types: [closed]
+    branches: [main]
+
+permissions:
+  contents: write
+
+jobs:
+  tag:
+    if: github.event.pull_request.merged == true
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Fetch tags
+        run: git fetch --tags --force
+
+      - name: Determine bump from PR labels
+        id: bump
+        shell: bash
+        env:
+          PR_LABELS: ${{ toJson(github.event.pull_request.labels) }}
+        run: |
+          labels=$(echo "$PR_LABELS" | jq -r '.[].name' | tr '[:upper:]' '[:lower:]')
+          echo "PR labels: $labels"
+
+          # If 'no-tag' present, skip tagging entirely.
+          if echo "$labels" | grep -q '\bno-tag\b'; then
+            echo "skip=true" >> "$GITHUB_OUTPUT"
+            echo "Tagging skipped due to 'no-tag' label."
+            exit 0
+          fi
+
+          level="patch" # default
+          if   echo "$labels" | grep -q '\bmajor\b'; then level="major"
+          elif echo "$labels" | grep -q '\bminor\b'; then level="minor"
+          elif echo "$labels" | grep -q '\bpatch\b'; then level="patch"
+          fi
+
+          echo "level=$level" >> "$GITHUB_OUTPUT"
+          echo "Selected bump: $level"
+
+      - name: Compute next tag
+        id: next
+        if: steps.bump.outputs.skip != 'true'
+        shell: bash
+        env:
+          LEVEL: ${{ steps.bump.outputs.level }}
+        run: |
+          latest="$(git tag --list 'v*.*.*' | sort -V | tail -n1)"
+          if [[ -z "$latest" ]]; then
+            latest="v0.1.0"
+            echo "No previous tag; starting at $latest"
+          fi
+          ver="${latest#v}"
+          IFS='.' read -r MA MI PA <<<"$ver"
+
+          case "$LEVEL" in
+            major) MA=$((MA+1)); MI=0; PA=0 ;;
+            minor) MI=$((MI+1)); PA=0 ;;
+            patch|*) PA=$((PA+1)) ;;
+          esac
+
+          next="v${MA}.${MI}.${PA}"
+          echo "next=$next" >> "$GITHUB_OUTPUT"
+          echo "latest=$latest -> next=$next"
+
+      - name: Tag and push
+        if: steps.bump.outputs.skip != 'true'
+        env:
+          NEXT: ${{ steps.next.outputs.next }}
+        run: |
+          if git rev-parse -q --verify "refs/tags/${NEXT}" >/dev/null; then
+            echo "Tag ${NEXT} already exists; nothing to do."
+            exit 0
+          fi
+          git config user.name  "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+          git tag -a "$NEXT" -m "chore(release): $NEXT"
+          git push origin "$NEXT"
+
+      - name: Comment with result
+        if: steps.bump.outputs.skip != 'true'
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const next = '${{ steps.next.outputs.next }}';
+            const level = '${{ steps.bump.outputs.level }}';
+            github.rest.issues.createComment({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.payload.pull_request.number,
+              body: `🔖 Released **${next}** (bump: \`${level}\`).`
+            });
+
+      - name: Comment: tagging skipped
+        if: steps.bump.outputs.skip == 'true'
+        uses: actions/github-script@v7
+        with:
+          script: |
+            github.rest.issues.createComment({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.payload.pull_request.number,
+              body: `⏭️ Tag creation skipped due to \`no-tag\` label.`
+            });