Function validate_preset_values 

pub fn validate_preset_values(
    commands: &BTreeMap<String, CommandSpec>,
    schema: &Schema,
) -> Result<(), String>

Always-on: validate preset YAML options: values against declared choices: in the schema. An option YAML value whose key matches a declared option with a choices: list must be one of those choices. Keys not declared in the schema are ignored here — those are the concern of validate_presets_strict (opt-in).

Used for whole-map validation (e.g. from a future fdl config lint subcommand). The dispatch path uses validate_preset_for_exec so sibling-preset typos don’t block correct invocations.