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/localGeojson.analyst.test.mjs

@@ -2,7 +2,18 @@
 import { test } from 'node:test';
 import assert from 'node:assert/strict';
 import * as Cesium from 'cesium';
-import { createLocalGeoJsonLayer, mapAnalystRecord } from './localGeojson.js';
+import { localGeoJsonServices } from '../app/localGeojsonServices.js';
+import {
+  createLocalGeoJsonLayer as createLayer,
+  mapAnalystRecord,
+} from './localGeojsonCore.js';
+
+/** The catalog's services, with the overlay host each test supplies. */
+const createLocalGeoJsonLayer = (options) =>
+  createLayer(options, {
+    ...localGeoJsonServices,
+    overlayHost: options.overlayHost,
+  });
 
 const DC_RAW = {
   id: '1176042553',