Merge branch 'main' into feat/aqhi

Port to current main: main reserved layer-state token 0 for street-level, so
air-quality takes the next free token, 4 (registry, ledger, and the allocation
tests shift by one). Main moved source contracts into sourceComposition.js, so
air-quality registers its getSnapshot contract there. Package boundaries keep
main's lists plus this branch's air-quality modules and packages.

src/app/constructCatalog.test.mjs

@@ -5,6 +5,7 @@ import { createApplicationCatalog } from './constructCatalog.js';
 import { createStandaloneLayerSources } from '../standalone/layerSources.js';
 import { catalogControlServices } from './catalog.js';
 import { LayerLifecycle } from '../data/lifecycle.js';
+import { fakeStreetLevelProvider } from '../testSupport/streetLevelFakes.mjs';
 
 function fixtureSources(ids, calls) {
   const sources = createStandaloneLayerSources();
@@ -39,7 +40,7 @@ test('catalogs construct distinct layers and classification from their supplied
     signal: b.signal,
     surface: fixtureSurface(b.signal),
   });
-  assert.equal(first.layers.length, 30);
+  assert.equal(first.layers.length, 32);
   assert.ok(first.get('local-adsb'), 'Local ADS-B is registered');
   assert.deepEqual(
     first.metadata.find(({ id }) => id === 'local-adsb'),
@@ -59,6 +60,7 @@ test('catalogs construct distinct layers and classification from their supplied
       '2026-09-21T12:00:00.000Z',
     );
   assert.ok(first.get('fire-perimeters'));
+  assert.ok(first.get('gnss-integrity'));
   assert.ok(first.get('transit'));
   const order = first.layers.map(({ id }) => id);
   assert.deepEqual(
@@ -116,7 +118,7 @@ test('invalid or already cancelled construction fails before classification can
   assert.throws(
     () =>
       createApplicationCatalog({
-        sources: {},
+        sources: { flights: {} },
         signal: lifetime.signal,
         surface: fixtureSurface(lifetime.signal),
       }),
@@ -140,3 +142,53 @@ function fixtureSurface(signal) {
     eventTarget: null,
   });
 }
+
+test('Mapillary can be omitted or replaced without changing catalog membership', (t) => {
+  const lifetime = new AbortController();
+  t.after(() => lifetime.abort());
+  const sources = fixtureSources([], []);
+  delete sources.mapillary;
+  const options = {
+    sources,
+    signal: lifetime.signal,
+    surface: fixtureSurface(lifetime.signal),
+  };
+  const catalog = createApplicationCatalog(options);
+  assert.equal(catalog.layers.length, 32);
+  assert.deepEqual(catalog.get('street-level').providerIds, []);
+  assert.equal(
+    catalogControlServices(catalog).streetLevelLayer,
+    catalog.get('street-level'),
+  );
+  assert.match(
+    catalog.get('street-level').getUIState().coverage.hint,
+    /No street-level imagery providers/,
+  );
+  const provider = fakeStreetLevelProvider({
+    id: 'example',
+    pickPrefix: 'example:',
+  });
+  const replacement = createApplicationCatalog({
+    ...options,
+    streetLevelProviders: [provider],
+  });
+  assert.deepEqual(replacement.get('street-level').providerIds, ['example']);
+  assert.deepEqual(replacement.metadata, catalog.metadata);
+  assert.equal(provider.calls.activate, 0, 'construction must not acquire');
+  assert.deepEqual(
+    createApplicationCatalog({
+      ...options,
+      sources: fixtureSources([], []),
+      streetLevelProviders: [],
+    }).get('street-level').providerIds,
+    [],
+  );
+  assert.throws(
+    () =>
+      createApplicationCatalog({
+        ...options,
+        sources: { ...sources, mapillary: {} },
+      }),
+    /Mapillary source/,
+  );
+});