feat: publish multi-precision RVQ encoders

[apage224]

Export and evaluate FP32, INT8, FP16, and INT16x8 RVQ encoders with per-precision release reports and runtime loading support.

Closes #64.

Changes

• Add calibration, encoder quantization evaluation, deployment metadata, and Hugging Face publication support.
• Keep repackaged sample artifacts synthetic; real calibration and evaluation frames remain separate from those samples.
• Deduplicate frame content before splitting calibration and evaluation data, and support encoder evaluation with a Keras-only decoder.
• Integrate current main and migrate release documentation to Astro.

Validation

• Full devcontainer suite: 426 passed, 78 skipped for optional artifacts/data.
• Ruff, formatting, shell syntax, GitHub CI, and Astro documentation checks pass at bd52430.
• Independent review verified the synthetic sample, duplicate-frame, and Keras-only decoder fixes; no remaining actionable findings.

Related repair

Merge companion #75 before publishing regenerated RVQ deployment bundles. It fixes EMA codebook extraction and adds independent training-to-deployment parity validation.

[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).

[apage224]

Resolved the integration conflicts and all three independent-review findings: synthetic release samples, duplicate-frame calibration/evaluation overlap, and the Keras-only decoder path. A follow-up independent review found no remaining actionable findings.

At bd52430, the full devcontainer suite passed 426 tests (78 optional artifacts/data skips). GitHub CI and Astro documentation checks both passed. This PR is now ready for review and merge, with no merge conflicts. Companion #75 should merge next before regenerated RVQ deployment bundles are published.