docs(street-level): shorten docs and comments before merge

Trim the doc text this PR adds (README, CHANGELOG, CURRENT-STATE,
KNOWN-ISSUES, SECURITY, DATA_SOURCES, .env.example, the CI job comment),
drop code comments that restate the code, cut design-note JSDoc to a line
or two, and drop review tags from test names. Comments only; no code
changes.

Also: README key count (seven keys, two metered), CURRENT-STATE's gate
paragraph (CI runs a production build with a dummy token), the stacked
doc above meshBoxInRange and the orphaned inMeshRange line in
coverage.js, and a duplicate ALPR row in DATA_SOURCES that a merge had
brought back.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/layers/streetLevel/marker.js

@@ -6,11 +6,7 @@ import { createHorizonCull } from './view.js';
 
 const SPRITE_ID = 'street-level:marker';
 
-/**
- * The on-globe marker for the image the viewer currently shows. In terrain
- * mode (Google 3D at street zoom) it stands on the bare earth instead of
- * clamping to the top of the photoreal mesh.
- */
+/** On-globe marker for the open image; in terrain mode it stands on bare earth. */
 export function createMarker({ state, parts }) {
   const { render, sprites } = state.services;
   let last = null;
@@ -36,9 +32,8 @@ export function createMarker({ state, parts }) {
   }
 
   /**
-   * Height for the position in terrain mode: bare earth, refined by the
-   * sampled Google 3D surface where it is known; null to clamp. Fetches a
-   * missing terrain cell and asks for a mesh sample under the marker.
+   * Terrain-mode height (bare earth refined by mesh samples), or null to
+   * clamp. Requests a missing terrain cell or mesh sample as a side effect.
    */
   function castHeight(position) {
     const ground = parts?.groundCaster;