Fix mel regression

[beveradb]

PR: Fix Mel Roformer regression, add integration coverage, bump version to 0.38.1

• Fix: Restore Mel Roformer model loading broken in v0.38.0.

  • Stop passing unsupported kwargs to MelBandRoformer (removed fmin, fmax, mel_scale).
  • Propagate optional, legacy-compatible kwargs (e.g., mask_estimator_depth, STFT and multi-STFT settings, match_input_audio_length) when present.
  • Add resilient legacy load path: on new-path failure (RuntimeError, ValueError, TypeError), instantiate model from original config (config['model'] if nested) and load checkpoint state_dict directly, then .to(device).eval().
  • Broaden exception catching around new path and legacy fallback.

• Tests: Add Mel model to integration suite and commit reference artifacts.

  • tests/integration/test_cli_integration.py: add
    • ("mel_band_roformer_karaoke_aufr33_viperx_sdr_10.1956.ckpt", ["mardy20s_(Instrumental)_mel_band_roformer_karaoke_aufr33_viperx_sdr_10.flac", "mardy20s_(Vocals)_mel_band_roformer_karaoke_aufr33_viperx_sdr_10.flac"])
  • Commit generated outputs in tests/inputs/ and reference images in tests/inputs/reference/.
  • Input reference images updated (regenerated).

• Version: Bump pyproject.toml version to 0.38.1.

• Rationale

  • v0.38.0 introduced a unified loader; Mel models failed due to unsupported kwargs and constructor/state_dict mismatches.
  • This change unblocks users immediately while preserving the new path; legacy fallback keeps backward compatibility with existing checkpoints.

• Impact and compatibility

  • New path still preferred; transparent fallback ensures older Mel/BS checkpoints load.
  • No behavioral change for non-Roformer models.
  • Improved logs on fallback.

• Follow-ups (not included here)

  • Clean up legacy path once config normalization fully covers all legacy variants.
  • Tighten validator/normalizer to prevent unsupported arg propagation and ensure strict param mapping across Roformer variants.