* Audio: migrate file decoding to symphonia 0.6
Upstream bumped symphonia to 0.6 without adapting crates/audio-io, so
`soundcraft-audio-io` no longer built: the probe module, codec parameters
and decoded-buffer APIs all moved.
- Probe with `default::get_probe().probe(&Hint, …)`. The 0.5 prober's
detection-only path is gone, so scan for the container marker ourselves
before instantiating a reader, and keep running the existing size checks
(CAF/MP4/FLAC/WAV) on the first marker — the damaged-file regression
tests depend on those checks firing before any allocation.
- Skip leading ID3v2 tags with `ReadBytes::ignore_bytes` as before.
- Read `Track::codec_params` (now an `Option`), decode through
`make_audio_decoder` and `GenericAudioBufferRef::copy_to_vecs_planar`,
and read the new public `Packet` fields.
- Keep the per-packet frame limit and the sample sanitisation.
* Playback: migrate the audio device layer to cpal 0.18
- Sample rates are plain `u32` now: drop `.0` and the `cpal::SampleRate`
constructor.
- One `cpal::Error` replaces the build/stream/play/pause error types;
detect `DeviceNotAvailable` through `error.kind()`.
- Stream builders take `StreamConfig` by value, and device names come
from `Device::description()` (the deprecated `name()` is gone).
- The test `Fake` implements the new `StreamTrait::{buffer_size, now}`.
* Deps: pin egui back to 0.36 until craft-ui supports 0.37
The dependabot group bump (#767) moved the workspace to egui, eframe and
egui_kittest 0.37, but the pinned `craft-ui` revision still builds against
egui 0.36, so the graph carries two incompatible egui versions and
`soundcraft-ui-egui` does not compile. craft-libs#199 updates craft-ui to
0.37 and is still open; pin 0.36 and refresh the lockfile meanwhile. The
other version bumps from #767 stay.
Re-land egui 0.37 together with the craft-ui update.
* Audio: refuse a size-checked container the probe did not validate
The dependency-migration review showed the preflight size checks can
validate one container marker while symphonia's probe selects a different
container, so a misleading marker could skip the FLAC/MP4/CAF/WAVE checks.
Probe 0.6 reports the selected format only through the reader it returns,
so `open()` now records which container's checks ran (including the
RF64/BW64 RIFF forms) and refuses the stream when a size-checked reader
was chosen without its checks, before any packet is decoded. Markers found
in audio data of non-container streams (MP3, Ogg, AIFF) do not reject
valid files.
Adds a regression test with a fake RIFF prefix followed by a valid FLAC
stream, and doc comments for the functions touched by the dependency
migration (the review's docstring-coverage warning).
