The player always opened the system default output device. On a
Raspberry Pi that default is often HDMI, so playback ran but nothing
came out of the headphone jack or a USB/DAC -- "it plays but I hear no
sound".
Add an [audio] device option to crabidy-server.toml: a case-insensitive
substring of the output device name (a memorable fragment is enough).
The player engine opens the first matching device and falls back to the
system default with a warning if none matches. Absent config keeps the
system default, so existing setups are unchanged.
To discover the names, a new `crabidy-server audio-devices` subcommand
(also on `cbd`) lists the output devices and marks the one the current
config selects, using the same match the server applies at startup.
Plumbing: audio_player::output_device_names() enumerates via cpal;
Player::new(Option<String>) replaces the device-less construction
(Default = new(None)); Playback::new takes the device and serve() reads
it from settings. cpal's name() is deprecated in favor of description(),
but name() returns the ALSA-stable string users see in `aplay -l` and
match against, so it is kept behind a documented #[allow(deprecated)].
README documents the [audio] device option under the Pi/config section.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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