Publish Vulpes Preview 15 sources for desktop, Android and Tundra

Share Gaia assets and adapters, keep private profiles and development documents local, and update both public READMEs.

overrides/search.gaiamobile.org/home-bridge.js

@@ -0,0 +1,25 @@
+// The local page follows Gaia's language, independently of Gecko's locale.
+let welcomeLanguage=navigator.language;
+function sendWelcomeLanguage() {
+  document.getElementById('vulpes-local-home')?.contentWindow.postMessage({
+    type:'vulpes-welcome-language',language:welcomeLanguage
+  },location.origin);
+}
+if(navigator.mozSettings) {
+  const request=navigator.mozSettings.createLock().get('language.current');
+  request.onsuccess=()=>{welcomeLanguage=request.result['language.current'] || navigator.language;sendWelcomeLanguage();};
+  navigator.mozSettings.addObserver('language.current',event=>{
+    welcomeLanguage=event.settingValue || navigator.language;sendWelcomeLanguage();
+  });
+}
+// Only the bundled welcome frame may request browser navigation.
+addEventListener('message', event => {
+  const frame=document.getElementById('vulpes-local-home');
+  if(event.source!==frame?.contentWindow || event.origin!==location.origin) return;
+  if(event.data?.type==='vulpes-welcome-ready'){sendWelcomeLanguage();return;}
+  if(event.data?.type!=='vulpes-welcome-open') return;
+  let url;
+  try { url=new URL(event.data.url); } catch (_) { return; }
+  if(!['http:','https:'].includes(url.protocol)) return;
+  new MozActivity({name:'view',data:{type:'url',url:url.href}});
+});