CI: trigger release on tag push, auto-create GitHub Release

Workflow now triggers on `v*` tag push instead of manual release.
Adds github-release job that creates a Release with auto-generated
notes and attaches all built artifacts.

Flow: git tag v2.0.0 && git push --tags → build → TestPyPI → PyPI → GH Release

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: desty2k

.github/workflows/deploy-pypi.yml

@@ -1,11 +1,12 @@
-name: Publish to PyPI
+name: Release
 
 on:
-  release:
-    types: [published]
+  push:
+    tags: ["v*"]
 
 permissions:
   id-token: write
+  contents: write
 
 jobs:
   build-sdist:
@@ -84,3 +85,22 @@ jobs:
           path: dist/
 
       - uses: pypa/gh-action-pypi-publish@release/v1
+
+  github-release:
+    name: Create GitHub Release
+    needs: [publish-pypi]
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: actions/download-artifact@v8
+        with:
+          pattern: dist-*
+          merge-multiple: true
+          path: dist/
+
+      - uses: softprops/action-gh-release@v2
+        with:
+          generate_release_notes: true
+          files: dist/*