Add HttpStatusCode (net)

[vhrcgcom]

Description

Implement HttpStatusCode as a ValueObject in the net module.

Spec: u16 in range 100–599

Implementation checklist

• Create src/net/httpstatuscode.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	u16	HttpStatusCodeInput
Output	u16	HttpStatusCodeOutput

Normalization

None.

Validation

• Must be in the range 100..=599.

Extra methods

• is_informational() -> bool — true for 1xx codes.
• is_success() -> bool — true for 2xx codes.
• is_redirection() -> bool — true for 3xx codes.
• is_client_error() -> bool — true for 4xx codes.
• is_server_error() -> bool — true for 5xx codes.

References

• ROADMAP.md
• CONTRIBUTING.md