Validate configurations comprehensively

When implementing configuration systems, ensure comprehensive validation, testing, and documentation. Key requirements:

1. Use an allowlist approach - explicitly categorize and validate ALL configuration fields
2. Test both serialization and deserialization of configuration
3. Document validation rules and error messages clearly
4. Handle environment variable overrides systematically

Example: ```rust #[derive(Serialize, Deserialize, Debug)] pub struct Config { // Explicitly document field purpose /// Controls daemon behavior, defaults to false in CI pub daemon: Option,

// Add validation methods
pub fn validate(&self) -> Result<(), Error> {
    // Explicit validation logic
} }

#[cfg(test)] mod tests { #[test] fn test_config_serialization() { // Test both serialization and deserialization let json = r#”{ “daemon”: true }”#; let config: Config = serde_json::from_str(json).unwrap(); assert_eq!(config.daemon, Some(true));

    let serialized = serde_json::to_string(&config).unwrap();
    assert_eq!(serialized, json);
} }