B6: release automation workflow

.github/workflows/release.yml

@@ -0,0 +1,63 @@
+name: Release
+
+# Triggers on either:
+#   - pushing a tag matching v*.*.* (e.g. v1.1.0)
+#   - publishing a GitHub Release manually from the UI
+#
+# Builds an sdist + wheel from pyproject.toml and attaches them to the
+# Release for that tag. The Release itself can be created manually or
+# automatically by `softprops/action-gh-release` if it doesn't exist yet.
+
+on:
+  push:
+    tags:
+      - "v*.*.*"
+  release:
+    types: [published]
+
+permissions:
+  contents: write  # needed to upload assets to the Release
+
+jobs:
+  build-and-attach:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Verify tag matches pyproject version
+        run: |
+          TAG="${GITHUB_REF_NAME#v}"
+          PROJECT_VERSION=$(python -c "import tomllib; print(tomllib.loads(open('pyproject.toml','rb').read().decode())['project']['version'])")
+          echo "Tag version:     $TAG"
+          echo "Project version: $PROJECT_VERSION"
+          if [ "$TAG" != "$PROJECT_VERSION" ]; then
+            echo "::error::Tag $GITHUB_REF_NAME does not match pyproject version $PROJECT_VERSION. Bump version in pyproject.toml before tagging."
+            exit 1
+          fi
+
+      - name: Build sdist and wheel
+        run: |
+          python -m pip install --upgrade pip build
+          python -m build
+
+      - name: List build artifacts
+        run: ls -la dist/
+
+      - name: Upload artifacts to workflow run
+        uses: actions/upload-artifact@v4
+        with:
+          name: dist-${{ github.ref_name }}
+          path: dist/
+
+      - name: Attach to GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          files: dist/*
+          fail_on_unmatched_files: true
+          # If the Release for this tag doesn't already exist, this action
+          # will create one. Body / title can be edited in the UI after.
+          generate_release_notes: true

CHANGELOG.md

@@ -22,6 +22,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Issue and pull request templates under `.github/`.
 - Dependabot configuration for weekly dependency and Actions updates.
 - `.env.example` documenting the supported environment variables.
+- Release automation workflow (`.github/workflows/release.yml`): on
+  pushing a `v*.*.*` tag, builds the sdist and wheel from
+  `pyproject.toml` and attaches them to the GitHub Release. Verifies the
+  tag matches the project version to prevent mismatched artifacts.
 - CodeQL workflow (`.github/workflows/codeql.yml`) running GitHub's
   `security-and-quality` Python query suite on every push, PR, and
   weekly. Findings surface under the repo's Security tab.