Merge main and switch Cesium and Navara in place through Vue

Preserve the camera, map source and layer selection across engine sessions. Restore the previous engine if startup fails and retain local history navigation.

scripts/qa-transit-heading.mjs

@@ -1,6 +1,7 @@
 import puppeteer from 'puppeteer';
 import { blockPaidQaMaps } from './qa-map-policy.mjs';
 import { transitQaBase } from './qa-transit-browser.mjs';
+import { chromeExecutablePath } from './qa-chrome.mjs';
 
 /** Prove parked and moving headings in the real scene, without live feeds. */
 export async function runTransitHeadingRegression(base, check) {