Add PyPI release workflow with trusted publishing (#20)

Adds GitHub Actions workflow that publishes to PyPI when a release is created.
Uses OIDC trusted publishing (no API tokens needed).

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: nhorton

.github/workflows/release.yml

@@ -0,0 +1,52 @@
+name: Release to PyPI
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v4
+        with:
+          version: "latest"
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+
+      - name: Install dependencies
+        run: uv sync --extra dev
+
+      - name: Run tests
+        run: uv run pytest tests/ -v
+
+      - name: Build package
+        run: uv build
+
+      - name: Upload dist artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: dist
+          path: dist/
+
+  publish:
+    needs: build
+    runs-on: ubuntu-latest
+    environment: pypi
+    permissions:
+      id-token: write
+    steps:
+      - name: Download dist artifacts
+        uses: actions/download-artifact@v4
+        with:
+          name: dist
+          path: dist/
+
+      - name: Publish to PyPI
+        uses: pypa/gh-action-pypi-publish@release/v1