End-to-end watermarker driver that handles any source sample rate by
resampling to AudioSeal's 16 kHz native, embedding, then resampling back.
Tested on 10s of real CSM 24 kHz speech: mean_presence=0.9988 detection,
12/16 message bits round-trip (4-bit erosion from double resample).
- examples/audioseal_apply.rs: --in/--out/--source-rate/--message; loads
source via audio_io::load_mono_at_rate, calls AudioSealWatermarker
through the public Watermarker trait, verifies via in-process detect.
- Fix bit-match counter overflow in audioseal_demo.rs and audioseal_apply.rs.
Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>
