holoconf-core: Configuration library with resolver support

This crate provides the core functionality for loading, parsing, and resolving configuration files with interpolation support.

Example

use holoconf_core::Config;

let yaml = r#"
database:
  host: localhost
  port: 5432
"#;

let config = Config::from_yaml(yaml).unwrap();
assert_eq!(config.get("database.host").unwrap().as_str(), Some("localhost"));