Add auto-publish workflow and bump CI actions

- Add publish.yml: builds and publishes to PyPI on GitHub Release,
  using Trusted Publishing (OIDC) so no API token is stored in the repo
- Bump actions/checkout to v5 and setup-python to v6 in ci.yml to
  resolve the Node.js 20 deprecation warning

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: SAKMZ

.github/workflows/ci.yml

@@ -15,10 +15,10 @@ jobs:
         python-version: ["3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
 
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python-version }}
 

.github/workflows/publish.yml

@@ -0,0 +1,44 @@
+name: Publish to PyPI
+
+# Publishes to PyPI whenever a GitHub Release is published.
+# Uses PyPI Trusted Publishing (OIDC) - no API token is stored in the repo.
+on:
+  release:
+    types: [published]
+
+jobs:
+  build:
+    name: Build distributions
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+      - uses: actions/setup-python@v6
+        with:
+          python-version: "3.12"
+      - name: Build sdist and wheel
+        run: |
+          python -m pip install --upgrade build
+          python -m build
+      - name: Check with twine
+        run: |
+          python -m pip install --upgrade twine
+          python -m twine check dist/*
+      - uses: actions/upload-artifact@v4
+        with:
+          name: dist
+          path: dist/
+
+  publish:
+    name: Publish to PyPI
+    needs: build
+    runs-on: ubuntu-latest
+    environment: pypi
+    permissions:
+      id-token: write  # required for trusted publishing (OIDC)
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          name: dist
+          path: dist/
+      - name: Publish to PyPI
+        uses: pypa/gh-action-pypi-publish@release/v1