Update shared Gaia workflows and Sargo development tooling

Fix camera switching and Contacts/SMS activity routing across shared hosts.
Integrate Marketplace installation and native standalone recovery tools,
Bluetooth runtime packages and trusted certificates.

Update English/French READMEs and the shared changelog with tested scope
and remaining radio/audio/Bluetooth limitations. Preview17 remains the
existing APK; no new native image is released.

Validation: shared JavaScript and native Python tests; Android packaging
and payload parity from an isolated publication checkout.

gaia/apps/ringtones/js/tone_player.js

@@ -143,7 +143,7 @@ TonePlayer.prototype = {
   _setExclusiveMode: function(exclusive) {
     if (exclusive) {
       if (!this._source) {
-        this._context = new AudioContext('ringer');
+        this._context = new AudioContext();
         this._source = this._context.createMediaElementSource(this._player);
         this._source.connect(this._context.destination);
       }