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.

tundra/tools/standalone_volume.py

@@ -0,0 +1,35 @@
+# SPDX-License-Identifier: MPL-2.0
+"""Validate the fresh userdata filesystem used by standalone Sargo images."""
+import json
+from pathlib import Path
+import re
+import uuid
+from tundra import digest
+
+
+def checked_volume(path, verify_image=True):
+    path = Path(path)
+    value = json.loads(path.read_text())
+    if (value.get('schema') != 1 or value.get('device') != 'sargo'
+            or value.get('storage') != 'raw-userdata-ext4'
+            or value.get('image') != 'userdata.ext4'
+            or value.get('filesystemCheckPassed') is not True):
+        raise ValueError('Expected a checked standalone Sargo volume')
+    identifier = value.get('uuid')
+    if not isinstance(identifier, str) or str(uuid.UUID(identifier)) != identifier:
+        raise ValueError('Invalid volume UUID')
+    for key in ('imageSha256', 'systemImageSha256'):
+        if not re.fullmatch(r'[a-f0-9]{64}', value.get(key, '')):
+            raise ValueError('Invalid '+key)
+    if type(value.get('bytes')) is not int or not 5*1024**3 <= value['bytes'] <= 32*1024**3:
+        raise ValueError('Invalid standalone filesystem size')
+    hardware = value.get('hardwareImages', {})
+    if hardware:
+        lock = json.loads((Path(__file__).resolve().parents[1]/'manifests/sargo-hardware.json').read_text())
+        if hardware != lock['images']:
+            raise ValueError('Unqualified standalone hardware images')
+    if verify_image:
+        image = path.parent/value['image']
+        if image.is_symlink() or image.stat().st_size != value['bytes'] or digest(image) != value['imageSha256']:
+            raise ValueError('Standalone volume changed')
+    return value