Map with coordinate regions and markers

[colemancda]

MapKit-style maps.

What's new

• Types — CLLocationCoordinate2D, MKCoordinateSpan, MKCoordinateRegion, MapMarker (title, coordinate, optional tint)
• Map(coordinateRegion:markers:) — emits a Map node carrying the region, with MapMarker children
• Interpreter renders a schematic map: the visible region maps linearly onto the box, markers sit at their proportional position (north at the top) with pin + label, and the center coordinate is captioned. Default fill-width × 220dp; .frame/.cornerRadius compose normally.

Real tile rendering is deliberately left to the composable registry — maps SDKs on Android require an API key, so the host app can register a tile-backed Map composable when it has one; the schematic keeps the core dependency-free.

Verification

• swift test — region + marker emission test, 57 passing
• Emulator (new Map screen): a Lima region with three tinted markers whose relative placement matches real geography (Plaza Mayor east of center, Miraflores south, Callao west), and a framed Cupertino region with its caption

Deferred

Region-change gestures (pan/zoom writing back to the binding); Marker-in-MapContentBuilder API form; tile providers.