chore: drop exports nothing imports

Knip, configured with the application, package exports, scripts, QA
harnesses, workers, tools and tests as entry points, reports exports
that no module imports. Each was checked by hand against string-based
and namespace imports.

- Symbols that are still used inside their own module lose only the
  `export` keyword (176 constants and helpers).
- Unused re-exports are removed from barrel modules (flight, military,
  vessel, CCTV, directions, transit history, local ADS-B and street-level
  policy modules).
- Declarations that nothing uses at all are deleted, among them
  AIS_WATCHDOG_STATUSES, applyFilter, isRadioCountryCode, compactText,
  DENSITY_STOPS, the unused CCTV endpoint constants, and the SDR band
  constants.
- Default exports that nothing imports are removed. The ones in
  src/data/earthquakes.js, src/data/telegeographySubmarineCables.js,
  src/data/wind.js and src/data/bhoteKoshiLocator.js each constructed a
  layer instance at import time that nothing used; those instances are
  no longer created.

Every export of a package.json entry stays, as does TOMTOM_CREDIT,
which the traffic layer reads from the credits namespace it is given.

src/voice/pointerContext.js

@@ -20,15 +20,15 @@
  */
 
 /** Movement below this many CSS pixels is still the same dwell. */
-export const POINTER_DWELL_PX = 12;
+const POINTER_DWELL_PX = 12;
 /** Stillness that makes a dwell point. */
 export const POINTER_DWELL_MS = 250;
 /** A resting pointer stays a referent this long after it last moved. */
 export const POINTER_FRESH_MS = 30000;
 /** Pixels from the canvas edge that count as "parked", never a referent. */
-export const POINTER_EDGE_PX = 8;
+const POINTER_EDGE_PX = 8;
 /** A dwell pick is reused by a snapshot only while this recent (contacts move). */
-export const POINTER_DWELL_REUSE_MS = 1000;
+const POINTER_DWELL_REUSE_MS = 1000;
 /**
  * Open mic has no gesture, so the pointer only counts when it moved or
  * settled on the map this recently: a cursor resting there for minutes is
@@ -76,7 +76,7 @@ export function cameraPoseKey(viewer) {
 }
 
 /** Bound and de-control a label before it goes to the model or the card. */
-export function pointerLabel(value, max = LABEL_MAX) {
+function pointerLabel(value, max = LABEL_MAX) {
   const clean = String(value ?? '')
     .replace(/[\p{Cc}\p{Cf}]+/gu, ' ')
     .replace(/\s+/g, ' ')