Establishes the constraint in godoc so future authors have a visible
signal before passing user-supplied values to session.CombinedOutput.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Introduces a standalone `soundtouch-backup` CLI with three subcommands:
- `all`: authenticates with the Bose cloud, backs up account data, then
reads device IPs from devices.xml and backs up each reachable speaker
- `cloud`: fetches account profile, devices, sources, presets, and full
endpoint from streaming.bose.com
- `local`: backs up each speaker via HTTP API (12 endpoints) and
optionally via SSH (individual files + /opt/Bose/etc/ and
/mnt/nv/BoseApp-Persistence/1/ directories)
Also centralises pkg/service/ssh → pkg/ssh so both the service and the
backup tool share the same SSH client; adds ReadFile and ReadDir
methods, and handles the firmware quirk where cat exits 1 on empty
files.
Output is a single dated .tar.gz or .zip archive.
Example flow:
```shell
gesellix@Mac Bose-SoundTouch % go run ./cmd/soundtouch-backup all --output _/cloud-backup --email user@example.com
Password:
Authenticating as user@example.com...
✓ Authenticated (account ID: 1234567)
✓ email address (107 bytes)
✓ devices (1492 bytes)
✓ sources (1111 bytes)
✓ presets (2585 bytes)
✓ full account (55037 bytes)
Found 2 device(s) in cloud account, attempting local backup...
✓ ST20: 12 files via HTTP
⚠ ST20: SSH skipped /etc/remote_services (Process exited with status 1)
⚠ ST20: SSH empty file /mnt/nv/remote_services
✓ ST20: 64 files via SSH
✓ ST10: 12 files via HTTP
⚠ ST10: SSH empty file /etc/remote_services
⚠ ST10: SSH skipped /mnt/nv/remote_services (Process exited with status 1)
✓ ST10: 48 files via SSH
Archive written: _/cloud-backup/soundtouch-backup-2026-05-02.tar.gz (141 files)
```
---------
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Tobias GesellchenandClaude Sonnet 4.6
