Release Android Preview 21 and bilingual changelog

Add permission-based reading of Android contacts, SMS and call history. Include shared Gaia fixes and document device validation limits. Pixel image qualification remains pending.

tests/keyboard-dictionaries.test.mjs

@@ -0,0 +1,24 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import vm from 'node:vm';
+import {readFileSync} from 'node:fs';
+const root=new URL('../',import.meta.url);
+const source=readFileSync(new URL('gaia/apps/keyboard/js/settings/layout_dictionary_downloader.js',root),'utf8');
+test('every offered Latin dictionary is present and has a valid header',()=>{
+  const layouts=JSON.parse(readFileSync(new URL('assets/webapps/keyboard.gaiamobile.org/js/settings/layouts.json',root)));
+  for(const name of new Set(layouts.filter(l=>l.imEngineId==='latin'&&l.dictFilename).map(l=>l.dictFilename))){
+    const data=readFileSync(new URL('gaia/apps/keyboard/js/imes/latin/dictionaries/'+name,root));
+    assert.equal(data.subarray(0,8).toString(),'FxOSDICT',name);
+  }
+});
+test('adding a language reads and verifies its local dictionary',async()=>{
+  let requested,aborted=false;
+  class XHR {
+    open(method,url){requested=url;}
+    send(){const b=readFileSync(new URL('gaia/apps/keyboard'+requested,root));this.response=b.buffer.slice(b.byteOffset,b.byteOffset+b.byteLength);this.onloadend();}
+    abort(){aborted=true;}
+  }
+  const window={};vm.runInNewContext(source,{window,XMLHttpRequest:XHR,ArrayBuffer,Uint8Array,Promise});
+  const data=await new window.LayoutDictionaryDownloader('latin','it.dict').load();
+  assert.equal(requested,'/js/imes/latin/dictionaries/it.dict');assert.ok(data.byteLength>8);assert.equal(aborted,false);
+});