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.

release.json

@@ -1,15 +1,15 @@
 {
   "gaia": "2.7.0",
   "channel": "preview",
-  "revision": 15,
-  "androidVersionCode": 15,
+  "revision": 17,
+  "androidVersionCode": 17,
   "geckoview": "156.0.20260921121718",
   "engineAlignment": {
     "family": "156",
     "patchParity": false,
     "reason": "Firefox desktop 156.0.1; Mozilla's GeckoView release repository currently offers 156.0 only. Keep the desktop patch and report actual engine versions."
   },
-  "version": "2.7-preview.15",
+  "version": "2.7-preview.17",
   "adapters": {
     "desktop": "0.1.0-dev",
     "android": "0.1.0-dev"