Cut duplicated and dead code across the engines, the layers and the QA scripts

- src/geo drops the ported debug argument checks and the tests that
  bitExact already covers; package boundaries accept a directory entry,
  so src/geo/ is listed once per group.
- Cesium no longer carries movers and lines nobody draws with: they are
  optional engine capabilities. The fake engine and the Cesium camera use
  the shared cameraMath; unused contract tables, clock.ticked, the
  'finest' surface detail and Navara click statistics are gone.
- ALPR keeps one overlay core and one presentation model for both
  engines, bikeshare one station bookkeeping, the Navara ground effects
  one definition helper; image atlases, view centres, mover banks and
  colours are shared.
- The legacy switch route, the clock offset and rate controls and other
  unused exports are removed.
- The acceptance runs the Navara draw, geo import and scope checks;
  scenarios use the harness switch and page helpers; the main chunk
  check keeps the size budget only and runs once in CI.

scripts/qa-weather-engine-switch.mjs

@@ -1,7 +1,12 @@
 import { fromDegrees } from '../src/geo/cartesian3.js';
 import sharp from 'sharp';
 import assert from 'node:assert/strict';
-import { createStrict, localPreview } from './qa-strict-harness.mjs';
+import {
+  createStrict,
+  localPreview,
+  openPage,
+  waitForEngine,
+} from './qa-strict-harness.mjs';
 
 const base = localPreview(process.argv[2]);
 base.search = '?engine=navara&welcome=0&look=cinematic';
@@ -16,14 +21,8 @@ const strict = createStrict({
     'weather-cyclones',
   ],
 });
-await strict.run({ args: ['--use-angle=metal', '--enable-gpu'] }, async (b) => {
-  const p = await b.newPage();
-  await p.setViewport({ width: 1024, height: 768 });
-  const errors = [];
-  p.on('pageerror', (e) => {
-    errors.push(e.message);
-    console.log('error', e.message.split('?')[0]);
-  });
+await strict.run({}, async (b) => {
+  const { page: p, errors } = await openPage(b);
   const times = ['2026-11-02T12:00:00.000Z', '2026-11-02T12:05:00.000Z'];
   const ids = ['weather-radar', 'weather-satellite', 'weather-lightning'];
   const images = new Map(),
@@ -168,21 +167,7 @@ await strict.run({ args: ['--use-angle=metal', '--enable-gpu'] }, async (b) => {
       console.log('GPU', msg.text().slice(0, 3000));
   });
   await p.goto(base.href);
-  const ready = async (kind) => {
-    await p.waitForFunction(
-      (k) =>
-        window.__godsEyeView?.engine?.kind === k &&
-        !document.querySelector('#globe-engine')?.disabled &&
-        !document.querySelector('.engine-switch-frame') &&
-        document.querySelector('#loading-screen.hidden'),
-      { timeout: 90000 },
-      kind,
-    );
-    await p.evaluate(
-      () => window.__godsEyeView.styleManager.initialRestorePromise,
-    );
-  };
-  await ready('navara');
+  await waitForEngine(p, 'navara');
   const waitTime = (ids, time) =>
     p.waitForFunction(
       (ids, time) =>
@@ -251,8 +236,7 @@ await strict.run({ args: ['--use-angle=metal', '--enable-gpu'] }, async (b) => {
   const polls = [...reads.entries()];
   for (const kind of ['navara', 'cesium', 'navara']) {
     if ((await p.evaluate(() => window.__godsEyeView.engine.kind)) !== kind) {
-      await strict.pick(p, kind);
-      await ready(kind);
+      await strict.switchTo(p, kind);
     }
     await waitTime(ids, times[0]);
     const state = await p.evaluate(
@@ -364,7 +348,7 @@ await strict.run({ args: ['--use-angle=metal', '--enable-gpu'] }, async (b) => {
   for (const kind of ['navara', 'cesium', 'navara']) {
     if ((await p.evaluate(() => window.__godsEyeView.engine.kind)) !== kind) {
       await p.select('#globe-engine', kind);
-      await ready(kind);
+      await waitForEngine(p, kind);
     }
     await p.waitForFunction(
       () =>