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/data/cctvLod.js

@@ -94,7 +94,7 @@ export function incumbentRankKm(
 export const CCTV_CARD_CENTER_WEIGHT = 0.5;
 
 /** Robust pool-distance percentile used to scale the screen-space term. */
-export const CCTV_CARD_SPREAD_PERCENTILE = 0.9;
+const CCTV_CARD_SPREAD_PERCENTILE = 0.9;
 
 /** True only when both viewport dimensions are finite positive pixels. */
 export function hasFiniteCctvViewport(viewW, viewH) {
@@ -172,8 +172,8 @@ export function blendCenterRankKm(
 // viewport is bucketed into this grid and every occupied cell gets its best
 // candidate before global rank fills the rest. Owner-tunable together with
 // the budgets above.
-export const CCTV_CARD_GRID_COLS = 5;
-export const CCTV_CARD_GRID_ROWS = 4;
+const CCTV_CARD_GRID_COLS = 5;
+const CCTV_CARD_GRID_ROWS = 4;
 
 /**
  * Screen-space distribution pass (owner round 2, item C). Buckets the