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/runtime/prepare-bluetooth.py

@@ -0,0 +1,34 @@
+# SPDX-License-Identifier: MPL-2.0
+"""Connect the Sargo Bluetooth HAL to BlueZ; pairing stays user initiated."""
+
+def prepare(root, write):
+    write('etc/dbus-1/system.d/tundra-bluetooth.conf', '''<!DOCTYPE busconfig PUBLIC
+ "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
+ "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
+<busconfig><policy user="root"><allow own="org.bluez"/><allow send_destination="org.bluez"/></policy></busconfig>
+''')
+    write('etc/bluetooth/main.conf', '[General]\nName=Vulpes OS\nDiscoverableTimeout=120\n[Policy]\nAutoEnable=false\n')
+    write('etc/systemd/system/tundra-bluebinder.service', '''[Unit]
+Description=Sargo Bluetooth HAL bridge
+Requires=tundra-hal.service
+After=tundra-hal.service
+Before=bluetooth.service
+[Service]
+Type=notify
+ExecStartPre=/usr/bin/binder-wait android.hardware.bluetooth@1.0::IBluetoothHci/default
+ExecStart=/usr/sbin/bluebinder
+Restart=on-failure
+RestartSec=5
+TimeoutStartSec=60
+NoNewPrivileges=yes
+ProtectHome=yes
+ProtectSystem=strict
+PrivateTmp=yes
+''')
+    write('etc/systemd/system/bluetooth.service.d/tundra.conf', '''[Unit]
+Requires=tundra-bluebinder.service dbus.service
+After=tundra-bluebinder.service dbus.service
+''')
+    wants = root/'etc/systemd/system/tundra.target.wants'
+    wants.mkdir(parents=True, exist_ok=True)
+    (wants/'bluetooth.service').symlink_to('/usr/lib/systemd/system/bluetooth.service')