chore: remove four modules nothing in the app uses (#1403)

* chore: remove four modules nothing in the app uses

src/app/sourceSlot.js re-exported src/sources/sourceSlot.js, which every
caller imports directly. src/data/flowTiles.js and src/data/issPass.js were
reached only by their own tests. src/data/localGeojson.js wrapped
localGeojsonCore.js with the app's services, which the catalog already
passes itself. The local GeoJSON layer tests now build layers the way the
catalog does, so they keep covering localGeojsonCore.js; only the test of
the wrapper's own default host goes. Boundary lists, format scope and docs
drop the removed paths.

* docs: changelog for #1403

src/data/localGeojsonLifecycle.test.mjs

@@ -1,9 +1,17 @@
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import * as Cesium from 'cesium';
-import { createLocalGeoJsonLayer } from './localGeojson.js';
+import { localGeoJsonServices } from '../app/localGeojsonServices.js';
+import { createLocalGeoJsonLayer as createLayer } from './localGeojsonCore.js';
 import { getContextStore } from './contextStore.js';
 
+/** The catalog's services, with the overlay host each test supplies. */
+const createLocalGeoJsonLayer = (options) =>
+  createLayer(options, {
+    ...localGeoJsonServices,
+    overlayHost: options.overlayHost,
+  });
+
 const dataset = JSON.stringify({
   type: 'Feature', id: 'dam', properties: { name: 'Test dam' },
   geometry: { type: 'Polygon', coordinates: [[[0, 0], [0.01, 0], [0, 0.01], [0, 0]]] },