Add Port (net)

[vhrcgcom]

Description

Implement Port as a ValueObject in the net module.

Spec: u16 in range 1–65535

Implementation checklist

• Create src/net/port.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	PortInput
Output	u16	PortOutput

Normalization

None.

Validation

• Must be in the range 1..=65535. Port 0 is reserved and rejected.

Extra methods

• is_well_known() -> bool — true for ports 1–1023 (system / well-known ports).
• is_registered() -> bool — true for ports 1024–49151.
• is_dynamic() -> bool — true for ports 49152–65535 (ephemeral range).

References

• ROADMAP.md
• CONTRIBUTING.md