chore: remove unreachable legacy entry modules

Delete three modules that no entry point, package export, test or script
imports:

- src/ui.js, a StyleManager subclass that pre-selected the standalone
  catalog. Application controls are built through src/app/controls.js
  and src/standalone/controls.js.
- src/standalone/ui.js, a bare re-export of StyleManager.
- src/data/localLayers.js, a list of default infrastructure, cable and
  FIRMS layer instances. The catalog builds these layers itself.

With src/ui.js gone, the import-direction check keeps a single
compatibility exception (server/providers/local.js to
server/standalone/key-setup.js), and its test now asserts that a
src/ui.js importing standalone code is rejected. The boundary and
format registries and the docs that named these files are updated.

scripts/package-boundaries.json

@@ -1852,7 +1852,6 @@
       "src/data/localGeojson.js",
       "src/data/localGeojsonCore.js",
       "src/data/localGeojsonLod.js",
-      "src/data/localLayers.js",
       "src/data/local_data/natural_earth/marine.json",
       "src/data/local_data/natural_earth/regions.json",
       "src/data/local_data/neighborhoods/san-francisco.json",