Constant KNOWN_KEYS 

pub const KNOWN_KEYS: &[(&str, &str)];

Known configuration keys with their type descriptors.

Each entry is (dot_path, type_descriptor) where type_descriptor is:

• "string" — free-form string value
• "enum:val1,val2,..." — one of the listed values
• "array:string" — array of strings (cannot be set via --set)