Add BoundingBox (geo)

[vhrcgcom]

Description

Implement BoundingBox as a ValueObject in the geo module.

Spec: composite: SW Coordinate + NE Coordinate

Implementation checklist

• Create src/geo/boundingbox.rs
• Implement ValueObject trait
• Add #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
• Export from src/geo/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

BoundingBox is a composite value object. Depends on Coordinate.

	Type
Input	BoundingBoxInput { south_west: Coordinate, north_east: Coordinate }
Output	String — e.g. "SW(49.0000, 12.0000) NE(51.0000, 16.0000)"

Validation

• The south-west latitude must be strictly less than the north-east latitude.
• The south-west longitude must be strictly less than the north-east longitude.

Extra methods

• south_west() -> &Coordinate
• north_east() -> &Coordinate
• contains(coord: &Coordinate) -> bool — returns true if the coordinate falls within the bounding box (inclusive on all edges).

References

• ROADMAP.md
• CONTRIBUTING.md