Add release workflow

Add a workflow_dispatch workflow that bumps the version (patch/minor/major),
creates a GitHub release with auto-generated notes, and updates the major
version tag.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.github/workflows/release.yml

@@ -0,0 +1,72 @@
+name: Release
+
+on:
+  workflow_dispatch:
+    inputs:
+      bump:
+        description: Version bump type
+        required: true
+        default: patch
+        type: choice
+        options:
+          - patch
+          - minor
+          - major
+
+jobs:
+  release:
+    runs-on: ubuntu-latest-slim
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Determine new version
+        id: version
+        run: |
+          # Get the latest semver tag
+          LATEST_TAG=$(git tag --list 'v[0-9]*.[0-9]*.[0-9]*' --sort=-v:refname | head -n1)
+          if [ -z "$LATEST_TAG" ]; then
+            echo "No existing version tag found"
+            exit 1
+          fi
+
+          # Strip leading 'v' and split into components
+          VERSION="${LATEST_TAG#v}"
+          IFS='.' read -r MAJOR MINOR PATCH <<< "$VERSION"
+
+          case "${{ inputs.bump }}" in
+            major)
+              MAJOR=$((MAJOR + 1))
+              MINOR=0
+              PATCH=0
+              ;;
+            minor)
+              MINOR=$((MINOR + 1))
+              PATCH=0
+              ;;
+            patch)
+              PATCH=$((PATCH + 1))
+              ;;
+          esac
+
+          NEW_VERSION="v${MAJOR}.${MINOR}.${PATCH}"
+          echo "previous=$LATEST_TAG" >> "$GITHUB_OUTPUT"
+          echo "new=$NEW_VERSION" >> "$GITHUB_OUTPUT"
+          echo "major=v${MAJOR}" >> "$GITHUB_OUTPUT"
+          echo "Bumping $LATEST_TAG -> $NEW_VERSION"
+
+      - name: Create GitHub release
+        run: |
+          gh release create "${{ steps.version.outputs.new }}" \
+            --generate-notes \
+            --notes-start-tag "${{ steps.version.outputs.previous }}"
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Update major version tag
+        run: |
+          git tag -f "${{ steps.version.outputs.major }}" "${{ steps.version.outputs.new }}"
+          git push -f origin "${{ steps.version.outputs.major }}"