Function load_config 

pub fn load_config(
    cli_config_path: Option<&Path>,
    project_dir: &Path,
) -> Result<Config>

Load configuration with proper priority and merging.

Searches for config files in order of priority (lowest to highest):

1. ~/.config/nrs/config.toml (user-level, lowest priority)
2. .nrsrc.toml in project root (project-level)
3. CLI argument --config <path> (highest priority)

Configs are merged with higher priority configs overriding lower priority ones. Missing config files are handled gracefully (defaults are used).

Arguments

• cli_config_path - Optional path to config file specified via CLI argument
• project_dir - The project directory (where package.json is located)

Errors

Returns an error if a specified config file (via CLI) cannot be read or parsed. Missing default config files are not treated as errors.