Upload release wheels to GitHub releases

[Trinkle23897]

Summary

• add a post-PyPI publish step that creates the GitHub release when needed
• upload built wheels to the release page with --clobber so reruns are idempotent
• enable skip-existing for PyPI publish reruns after a partial release

Validation

• ruby -e 'require "yaml"; YAML.load_file(".github/workflows/release.yml"); puts "yaml ok"'
• git diff --check
• manually uploaded the v1.2.5 wheels from run 26184878430 to the release page and verified 16 assets