Check that an engine switch draws what a cold start from the share link draws

qa-switch-equals-cold-start switches engines in both directions with each
layer on deterministic fixtures, then opens the share link of the same
state in a new page on the target engine, and compares the draw ledgers
and the probe's view of the layer. It runs as 19 acceptance groups
covering all 38 layers.

State a layer keeps through a switch but the share link does not carry is
declared as sessionState (the directions route, Radio's selected station
and audio state, the wind reading, local ADS-B's and OSM Places' local
toggles and results); a test checks each declaration against what the
layer really retains, so a declaration cannot hide a regression.

src/layers/directions/index.js

@@ -1511,6 +1511,7 @@ export function createDirectionsLayer({
   };
   const directionsLayer = {
     id: 'directions',
+    sessionState: ['route'],
     name: 'Directions',
     icon: '🧭',
     source: 'OSM routing',

src/layers/localAdsb/index.js

@@ -606,6 +606,7 @@ export function createLocalAdsbLayer({
   const picks = { owner: LAYER_ID, predicate: (id) => markers.has(id) };
   return {
     id: LAYER_ID,
+    sessionState: ['enabled'],
     name: LAYER_NAME,
     icon: '📡',
     source: LAYER_SOURCE,

src/layers/osmPlaces/index.js

@@ -72,6 +72,7 @@ export function createOsmPlacesLayer({
 
   return {
     id: OSM_PLACES_LAYER_ID,
+    sessionState: ['enabled', 'results'],
     name: 'OSM Places',
     icon: '⌖',
     source: 'OpenStreetMap',

src/layers/radio/index.js

@@ -52,6 +52,7 @@ export function createRadioLayer({ services, source, rendererFactory }) {
     parts.lifecycle.methods,
     parts.ingestion?.methods,
     {
+      sessionState: ['selected', 'audioState'],
       radioGlobeLabel: parts.labels.radioGlobeLabel,
       createRadioSelectedOverlayEntry:
         parts.labels.createRadioSelectedOverlayEntry,

src/layers/wind/index.js

@@ -106,6 +106,7 @@ export function createWindLayer({
   const unsubscribeClock = clock?.subscribe(notify);
   const layer = {
     id: 'wind',
+    sessionState: ['reading'],
     name: 'Wind',
     icon: '🌬',
     source: 'GFS / ECMWF IFS · FORECAST',