feat: publish multi-precision RVQ encoders

[apage224]

Closes #64

Summary

• export FP32, INT8, FP16, and INT16x8 RVQ encoder variants
• add reproducible real-data quantization evaluation and per-precision release reporting
• add real PPG/ECG demo recording bundles and HF publication support

Validation

• focused export, runtime, quantization, and HF tests
• strict local package validation and Hub artifact verification

[apage224]

Release refresh complete.

• Republished all 11 PPG/ECG CR repositories with FP32, INT8, FP16, and INT16x8 encoder artifacts.
• Verified each Hub repo contains the four encoder files, real demo recordings, and an HF README with the precision-parity table.
• All 11 local deploy packages passed strict validation before upload.
• Focused release suite: 44 passed (one known SciPy warning).