Use Koruma

Follow the application workflow

1. Inspect the application's Cargo.toml, validated types, error consumers, and existing Koruma patterns. Preserve compatible dependency versions and feature choices.
2. Depend on koruma as the facade. Add koruma-collection when a built-in rule matches the requirement.
3. Use a custom #[validator] for domain-specific behavior, custom error data, or custom rendering.
4. Put every validator and modifier for a field in one #[koruma(...)] attribute. Configure validators with dot-chain setters and derive Koruma on the containing type.
5. Inspect failures through generated field and validator accessors. Add KorumaAllDisplay for displayable borrowed error variants or KorumaAllFluent for es-fluent rendering.
6. Use nested for a validated child object and newtype for transparent validation through an exactly-one-field wrapper. Select try_new, try_from, or try_from_inner according to the caller-facing construction API.
7. Update dependency features, imports, validation attributes, and error handling together.