refactor: enforce import directions and expose source factories

src/app/localGeojsonServices.js

@@ -0,0 +1,25 @@
+import { governorRequestRender } from '../renderGovernor.js';
+import {
+  clearSelectedEntityContextForLayer,
+  registerEntityContext,
+  removeEntityContextsForLayer,
+  selectEntityContext,
+} from '../data/contextStore.js';
+import {
+  clearOverlaySource,
+  setOverlayEntries,
+  setOverlaySourceVisible,
+} from '../overlays/worldOverlay.js';
+/** Existing standalone application operations, shared by its local layers. */
+export const localGeoJsonServices = Object.freeze({
+  overlayHost: Object.freeze({
+    clearSource: clearOverlaySource,
+    setEntries: setOverlayEntries,
+    setVisible: setOverlaySourceVisible,
+  }),
+  clearSelectedEntityContextForLayer,
+  registerEntityContext,
+  removeEntityContextsForLayer,
+  selectEntityContext,
+  governorRequestRender,
+});