Function check_handler_policy 

pub fn check_handler_policy(cmd_name: &str, key: &str, tokens: &[Token]) -> bool

Validate tokens against cmd_name’s named flag policy declared in a [command.handler_policy.KEY] block. Returns false if no such policy is declared or the tokens fail it. Used by handlers whose dispatch logic genuinely can’t move to TOML (e.g. gh’s sub × action matrix) but whose per-policy WordSets should live in TOML rather than as Rust WordSet constants.