Macro config_group 

macro_rules! config_group {
    ({
        $(
            $(#[$meta:meta])*
            ref $name:ident : $type:ty = $value:expr;
        )+
    }) => { ... };
}

Macro to create a configuration value group struct.

Usage:

use xet_runtime::config_group;

mod basic_group {
    use xet_runtime::config_group;

    config_group!({
        ref TEST_INT: usize = 42;
        ref TEST_STRING: String = "default".to_string();
    });
}

This creates a ConfigValueGroup struct with the specified fields, default values, environment variable overrides, and string-based accessors.

Python bindings are provided at the XetConfig level, not per-group.