Add Domain (net)

[vhrcgcom]

Description

Implement Domain as a ValueObject in the net module.

Spec: valid domain name without scheme

Implementation checklist

• Create src/net/domain.rs
• Implement ValueObject trait
• Add #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
• Export from src/net/mod.rs and prelude
• Unit tests: valid input · empty input · invalid format · normalisation
• Doc comment with # Example block
• Update status in ROADMAP.md from ⬜ to ✅

Implementation detail

Input / Output

	Type	Alias
Input	String	DomainInput
Output	String — lowercase	DomainOutput

Normalization

Trim, convert to lowercase.

Validation

• Must not contain a scheme (:// is forbidden — it is a hostname, not a URL).
• Each label (segment between dots) must be 1–63 characters.
• Labels may only contain ASCII letters, digits, and hyphens; no leading or trailing hyphen per label.
• At least one dot (single-label names like "localhost" are rejected).
• Total length must not exceed 253 characters.

Extra methods

• tld() -> &str — the last label after the final dot, e.g. "com", "cz".

References

• ROADMAP.md
• CONTRIBUTING.md