Add GitHub Actions workflow to publish to PyPI

Add .github/workflows/publish.yml to automatically build and publish the package when a release is published. The workflow runs on ubuntu-latest, sets up Python 3.12, installs build tools, creates distributions into dist/, uploads the built artifacts, and then downloads and publishes them to PyPI using pypa/gh-action-pypi-publish. The publish job is configured with an environment for PyPI and uses id-token: write for OIDC-based trusted publishing.

Author: petersenpeter

.github/workflows/publish.yml

@@ -0,0 +1,46 @@
+name: Publish to PyPI
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Install build tools
+        run: pip install build
+
+      - name: Build package
+        run: python -m build
+
+      - name: Upload distributions
+        uses: actions/upload-artifact@v4
+        with:
+          name: dist
+          path: dist/
+
+  publish:
+    needs: build
+    runs-on: ubuntu-latest
+    environment:
+      name: pypi
+      url: https://pypi.org/p/brainstem_python_api_tools
+    permissions:
+      id-token: write  # required for trusted publishing (OIDC)
+
+    steps:
+      - name: Download distributions
+        uses: actions/download-artifact@v4
+        with:
+          name: dist
+          path: dist/
+
+      - name: Publish to PyPI
+        uses: pypa/gh-action-pypi-publish@release/v1