8f4f8f3a14
Upload a file as an asset to an existing release. Completes the publishing workflow for extension .zip packages. Uses multipart form POST to Gitea's release assets endpoint. Safety: 100MB cap, requires absolute file_path, supports custom asset name (defaults to filename basename). Closes the gap in the release workflow: 1. create_release (existing) - creates the release 2. upload_release_attachment (NEW) - uploads the .zip/binary asset