Function github_token_env_hint 

pub fn github_token_env_hint() -> String

The env-var fragment of a “no GitHub token” remediation hint, rendered from GITHUB_TOKEN_ENV_LADDER in actual resolution-precedence order: ANODIZER_GITHUB_TOKEN or GITHUB_TOKEN or GH_TOKEN. Error messages interpolate this (or github_token_hint) instead of restating the vars, so a hand-spelled hint can never list the ladder in the wrong order or go stale when a var is added or renamed.