[11] Port the TCP105 voice-prompt playback

[jvwaldrich0]

Task 11 of 16 — these are sequential, do them in order.

Previous: #13 · Next: #15

Port target: cloudpark-toolkit (Go) → this repo (Rust). Reference paths below are relative to that repo.

Goal

Port the TCP105 voice-prompt playback so VoiceBroadcast commands are audible on the dev machine.

Scope

• Embed the wav set in the binary (include_bytes! / rust-embed), copied from cloudpark-toolkit/internal/tcp105/audio/files/*.wav.
• Map AudioID → wav file + human label (the label is what the log pane shows).
• Play through whatever is installed (paplay, aplay, ffplay) — detect once, fall back in order, and if none exists just log the prompt name instead of failing.
• Serialise playback so overlapping broadcasts queue rather than talk over each other.

Reference

cloudpark-toolkit/internal/tcp105/audio/audio.go + audio_test.go

Done when

• Test asserts every mapped AudioID resolves to an embedded file (no dangling entries).
• Playing an unknown AudioID logs a warning and continues.
• Works headless with no audio player installed.