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/build-standalone-volume.py

@@ -0,0 +1,83 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: MPL-2.0
+"""Build a fresh ext4 userdata image. No connection to a phone or partition writes."""
+import argparse
+import importlib.util
+import json
+import os
+from pathlib import Path
+import shutil
+import subprocess
+import sys
+import uuid
+from persistent_state import FEATURES
+from tundra import digest
+from standalone_volume import checked_volume
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('--prepared', required=True, type=Path)
+    parser.add_argument('--output', required=True, type=Path)
+    parser.add_argument('--hardware', type=Path, help='Locally supplied pinned vendor/modem images')
+    parser.add_argument('--size-mib', type=int, default=8192)
+    args = parser.parse_args()
+    if not 5120 <= args.size_mib <= 32768:
+        parser.error('Choose 5120–32768 MiB')
+    spec = importlib.util.spec_from_file_location('stage', Path(__file__).with_name('stage-sargo-files.py'))
+    stage = importlib.util.module_from_spec(spec); spec.loader.exec_module(stage)
+    files = stage.inputs(args.prepared)
+    hardware = {}
+    if args.hardware:
+        lock = json.loads((Path(__file__).resolve().parents[1]/'manifests/sargo-hardware.json').read_text())
+        hardware = lock['images']
+        for name, record in hardware.items():
+            source = args.hardware/record['source']
+            if source.is_symlink() or source.stat().st_size != record['bytes'] or digest(source) != record['sha256']:
+                raise ValueError('Hardware image changed: '+name)
+    payload_bytes = sum(p.stat().st_size for _,_,p,_ in files)
+    payload_bytes += sum(record['bytes'] for record in hardware.values())
+    if args.size_mib*1024**2 < payload_bytes+512*1024**2:
+        raise ValueError('Insufficient space for payload and filesystem metadata')
+    os.umask(0o077)
+    out = args.output.resolve(); out.mkdir(parents=True, exist_ok=False)
+    (out/'.incomplete').touch()
+    seed = out/'seed'; seed.mkdir()
+    for kind, name, source, record in files:
+        target = seed/'tundra'/kind/name; target.parent.mkdir(parents=True, exist_ok=True)
+        # mke2fs reads the file; a hard link avoids another multi-gigabyte copy.
+        os.link(source, target)
+    if hardware:
+        directory = seed/'tundra/hardware'; directory.mkdir()
+        for name, record in hardware.items():
+            os.link(args.hardware/record['source'], directory/name)
+    system = json.loads((args.prepared/'system.json').read_text())
+    state = json.loads((args.prepared/'data/state.json').read_text())
+    identifier = str(uuid.uuid4())
+    (seed/'tundra-volume-id').write_text(identifier+'\n')
+    image = out/'userdata.ext4'
+    with image.open('xb') as f: f.truncate(args.size_mib*1024**2)
+    subprocess.run(['mke2fs','-q','-t','ext4','-F','-b','4096','-I','256','-O',FEATURES,
+                    '-U',identifier,'-L','TUNDRA_VOLUME','-d',str(seed),str(image)],check=True)
+    names=['/tundra-volume-id','/tundra','/tundra/images','/tundra/data']
+    names += ['/tundra/'+kind+'/'+name for kind,name,_,_ in files]
+    if hardware:
+        names += ['/tundra/hardware', *['/tundra/hardware/'+name for name in hardware]]
+    for name in names:
+        for field in ('uid','gid'):
+            subprocess.run(['debugfs','-w','-R',f'set_inode_field {name} {field} 0',str(image)],check=True,stdout=subprocess.DEVNULL,stderr=subprocess.DEVNULL)
+    result = subprocess.run(['e2fsck','-f','-n',str(image)],capture_output=True,text=True)
+    (out/'filesystem-check.txt').write_text(result.stdout+result.stderr)
+    if result.returncode: raise ValueError('Standalone filesystem check failed')
+    manifest={'schema':1,'device':'sargo','storage':'raw-userdata-ext4','image':image.name,
+              'uuid':identifier,'bytes':image.stat().st_size,'imageSha256':digest(image),
+              'systemImageSha256':system['imageSha256'],'stateUuid':state['uuid'],
+              'filesystemCheckPassed':True,'flashReady':False,'hardwareImages':hardware,
+              'scope':'Fresh standalone storage; flashing userdata destroys previous user data'}
+    (out/'volume.json').write_text(json.dumps(manifest,indent=2)+'\n')
+    checked_volume(out/'volume.json')
+    (out/'.incomplete').unlink()
+    print(out/'volume.json')
+
+
+if __name__ == '__main__': main()