Adopt centralized craft-libs audio I/O (craft-audio-io) #1274

Summary

Audio I/O functionality originally authored in SoundCraft (soundcraft-audio-io) has been centralized into craft-libs (storytold/craft-libs#504) under the canonical craft-* namespace:

• craft-audio-io (Multi-format audio decoder/encoder supporting WAV, AIFF, FLAC, MP3, AAC, OGG Vorbis via Symphonia and pure-Rust writers)
• BS.1770 integrated loudness analysis & normalization
• Re-exported via craft-codecs umbrella crate

Motivation

Centralizing audio format reading and writing into craft-libs provides a single, audited source of truth across all ArtCraft applications (soundcraft, filmcraft, and encodercraft), eliminating duplicate decoder logic and ensuring memory-safe audio buffers with backpressure.

Next Steps

1. Add migration guide documenting the upstream location in craft-libs.
2. Transition internal soundcraft audio import/export pipelines to consume craft-audio-io from craft-libs.
3. Deprecate local crate in favor of upstream craft-libs dependency.