Function decode_node_id 

pub fn decode_node_id(id: &str) -> Option<(String, String)>

Decode a Relay global Node ID back to (type_name, uuid).

Returns None if the ID is not valid base64 or does not have the expected "TypeName:uuid" format.

Example

use fraiseql_core::runtime::relay::{decode_node_id, encode_node_id};

let id = encode_node_id("User", "550e8400-e29b-41d4-a716-446655440000");
let decoded = decode_node_id(&id);
assert_eq!(
    decoded,
    Some(("User".to_string(), "550e8400-e29b-41d4-a716-446655440000".to_string()))
);