"""Feature Definition Registry for AI MusiMuse.

This package provides the single source of truth for all feature
metadata produced by analyzers.  It defines:

- :class:`~features.definition.FeatureDefinition` — immutable metadata
  for one feature (identifier, display name, category, data type,
  normalization strategy, version)
- :class:`~features.registry.FeatureRegistry` — registration, lookup,
  and listing of feature definitions
- :func:`~features.default_registry.build_default_feature_registry` —
  factory that registers all features currently produced by the
  built-in analyzers

New analyzers should add their feature definitions to
:func:`~features.default_registry.build_default_feature_registry`.
"""