Add a GITEA_EXTRA_HEADERS environment variable that accepts a JSON
object of header name/value pairs (e.g. Cloudflare Access
credentials) and applies them to every outbound request to Gitea,
both the raw pkg/gitea.DoJSON/DoBytes path and the SDK-backed
pkg/gitea.NewClient path, without overriding Authorization,
Content-Type, or Accept.
Co-Authored-By: Codet <codet@commitgo.dev> (GPT-5-Codex)