- Add systemd drop-in override to fix StopWhenUnneeded auto-stop issue
- Add polkit rule for passwordless fcp-server management by audio group
- Improve post_install messages with troubleshooting guidance
- Add polkit to optdepends
This fixes the reliability issue where fcp-server would stop immediately
after being started by udev, preventing alsa-scarlett-gui from connecting.
Changes follow best practices:
- Drop-in override (non-invasive, survives upstream updates)
- Polkit rule follows PulseAudio/PipeWire precedent for audio group
- Comprehensive security review completed (see SECURITY_REVIEW.md)
- Focusrite Control Protocol user-space driver
- Supports Scarlett 4th Gen 16i16, 18i16, 18i20
- Includes systemd service and udev rules
- Auto-starts when device is connected
- Sets required CAP_SYS_RAWIO capability
