v0.58.0 — plane markers no longer teleport across the antimeridian (ISS-124)

planesGeoJson now takes the airport index and unwraps each flying plane's
longitude against its departure airport (unwrapLon, shared with unwrapLons),
mirroring routesGeoJson's both-endpoints guard so a marker is unwrapped iff
its line is drawn. Map.tsx passes airportsIndexRef at both call sites.

Unit +6 in lib/mapData.test.ts; e2e +1 in e2e/map-interactions.spec.ts
(chain-relocate to NZAA, fly the NZAA→NFTF crossing, sample marker lons).

lib/mapData.ts

@@ -41,15 +41,30 @@ export interface FeatureCollection<T> {
 const EMPTY_POINTS: FeatureCollection<MapPointFeature> = { type: 'FeatureCollection', features: [] };
 const EMPTY_LINES: FeatureCollection<MapLineFeature> = { type: 'FeatureCollection', features: [] };
 
-export function planesGeoJson(state: StateSnapshot | null): FeatureCollection<MapPointFeature> {
+// ISS-124 (v0.58.0): positionAt wraps each sample's longitude into [−180, 180], so a marker on a
+// leg crossing the antimeridian jumps +179.x → −179.x between polls — MapLibre draws that as a 360°
+// teleport while the route line (greatCircleArc) stays continuous. Unwrap the plane's lon against
+// its departure airport — the same anchor greatCircleArc keeps for its first sample — so marker and
+// line agree frame to frame. Only when BOTH endpoints exist, mirroring routesGeoJson's guard: a
+// flying plane with a missing endpoint draws no line either, so it stays wrapped like before.
+export function planesGeoJson(
+  state: StateSnapshot | null,
+  airportsByIcao: ReadonlyMap<string, AirportCoord>,
+): FeatureCollection<MapPointFeature> {
   if (!state) return EMPTY_POINTS;
   // Catalog display name ("ATR 72-600") for the popup — raw model id as fallback.
   const labelByModel = new Map(state.catalog.map((e) => [e.model, e.label]));
   const features: MapPointFeature[] = state.planes.map((p) => {
     const flying = p.status === 'flying';
+    let lon = p.lon;
+    if (flying && p.destIcao) {
+      const from = airportsByIcao.get(p.locationIcao);
+      const to = airportsByIcao.get(p.destIcao);
+      if (from && to) lon = unwrapLon(p.lon, from.lon);
+    }
     return {
       type: 'Feature',
-      geometry: { type: 'Point', coordinates: [p.lon, p.lat] },
+      geometry: { type: 'Point', coordinates: [lon, p.lat] },
       properties: {
         id: p.id,
         modelLabel: labelByModel.get(p.model) ?? p.model,
@@ -80,12 +95,16 @@ export const ROUTE_ARC_SEGMENTS = 24;
 // sequence into continuous longitudes: keep the first sample's raw lon, then shift each subsequent
 // one by ±360 relative to the previous UNWRAPPED value until |Δlon| ≤ 180. One line stays one line;
 // out-of-range values render on MapLibre's adjacent world copies (renderWorldCopies is default-on).
+function unwrapLon(lon: number, prev: number): number {
+  while (lon - prev > 180) lon -= 360;
+  while (prev - lon > 180) lon += 360;
+  return lon;
+}
+
 function unwrapLons(coords: [number, number][]): [number, number][] {
   let prev = coords[0]![0];
   for (let i = 1; i < coords.length; i++) {
-    let lon = coords[i]![0];
-    while (lon - prev > 180) lon -= 360;
-    while (prev - lon > 180) lon += 360;
+    const lon = unwrapLon(coords[i]![0], prev);
     coords[i]![0] = lon;
     prev = lon;
   }