Add PyPI trusted publishing via OIDC for tag builds

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: whtsky

.github/workflows/build.yml

@@ -44,4 +44,24 @@ jobs:
     - uses: actions/upload-artifact@v6
       with:
         name: sdist
-        path: dist/*.tar.gz
+        path: dist/*.tar.gz
+
+  publish:
+    name: Publish to PyPI
+    runs-on: ubuntu-latest
+    if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags')
+    needs: [build_wheels, make_sdist]
+    environment:
+      name: release
+      url: https://pypi.org/p/bencoder.pyx
+    permissions:
+      id-token: write
+    steps:
+    - name: Download all artifacts
+      uses: actions/download-artifact@v6
+      with:
+        path: dist/
+        merge-multiple: true
+
+    - name: Publish to PyPI
+      uses: pypa/gh-action-pypi-publish@release/v1