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/data/layerState.js

@@ -418,9 +418,8 @@ const OPTION_GROUPS = Object.freeze({
       pano: 'p',
       flat: 'f',
     }),
-    // "Captured since" as relative days, so a link means the same next year.
-    // The filter's MAX_SINCE_DAYS (streetLevel/policy.js); layerState.test
-    // pins the two together.
+    // Relative days, so a link means the same next year. The max matches
+    // MAX_SINCE_DAYS in streetLevel/policy.js (pinned by layerState.test).
     boundedIntegerOption('sinceDays', 's', 0, { min: 0, max: 36500 }),
   ]),
   radio: Object.freeze([