fix: use softprops/action-gh-release instead of gh CLI

gh CLI is not installed on the self-hosted runner. Switch to
softprops/action-gh-release@v2 which was used before the
standardization broke it.

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

.github/workflows/release.yaml

@@ -96,10 +96,11 @@ jobs:
           git push origin main --tags
 
       - name: Create GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          tag_name: "v${{ inputs.version }}"
+          files: ${{ env.TARBALL }}
+          fail_on_unmatched_files: true
+          generate_release_notes: true
         env:
-          GH_TOKEN: ${{ github.token }}
-        run: |
-          VERSION="${{ inputs.version }}"
-          gh release create "v${VERSION}" "${{ env.TARBALL }}" \
-            --title "v${VERSION}" \
-            --generate-notes
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}