fix(markers): render locally-dropped markers on the 2D engine (#77)

[jfuginay]

Root cause

File: app/src/main/kotlin/soy/engindearing/omnitak/mobile/ui/components/TacticalMap.kt, line 383 (removed)

The contact push inside TacticalMap was wired as:

DisposableEffect(mapView, contacts) {
    mapView.getMapAsync { map ->
        if (map.style != null) {           // ← silent drop during style load
            ContactLayer.update(map, context, contacts)
            contactSymbolLayer.update(map, context, contacts)
        }
    }
    onDispose { }
}

During the initial style-load window (100–2 000 ms), map.style != null is false. The update is silently dropped. The style-ready callback at line ~156 was meant to recover via currentContacts (rememberUpdatedState), but it fires only once. Any marker ingested after that first push and before the next Compose-triggered contacts key change was irretrievably lost — showing up on the Cesium 3D Globe (whose AndroidView.update { pushEntities() } retries on every recomposition) but never on 2D MapLibre.

What changed

TacticalMap.kt — removed DisposableEffect(mapView, contacts) and changed the terminal AndroidView from factory-only to factory + update:

AndroidView(
    factory = { mapView },
    update = {
        mapView.getMapAsync { map ->
            map.getStyle { _ ->                // queuing variant — never drops
                ContactLayer.update(map, context, currentContacts)
                contactSymbolLayer.update(map, context, currentContacts)
            }
        }
    },
    modifier = modifier,
)

Three deliberate changes vs the removed effect:

1. AndroidView.update { } fires on every recomposition that receives a new contacts list — identical cadence to the Cesium engine. The update retries on the next frame instead of being lost.
2. map.getStyle { } (queuing variant) instead of if (map.style != null): when the style is still loading the callback queues and fires when ready, closing the style-load race entirely.
3. currentContacts (rememberUpdatedState) inside the callback instead of the DisposableEffect-time snapshot — the async callback always sees the latest list.

ContactLayerFeatureTest.kt (new) — pure JVM test for the data-layer preconditions: every locally-dropped marker type (point-dropper, coordinate-entry, FEMA palette) produces finite lat/lon and a valid CSS hex color string, covering argbToHex edge cases and the NaN-guard contract that ContactLayer.update depends on.

Test evidence

./gradlew assembleDebug       → BUILD SUCCESSFUL
./gradlew testDebugUnitTest   → BUILD SUCCESSFUL (78 tasks, all green)

New test class: ContactLayerFeatureTest (14 tests).

On-device verification rides with the next closed-track build.