chameleon 4.4.49

Fixed

• The Python inheritance lint false-positived on every subscripted-generic base.
  Derivation strips the generic type-param (_strip_type_params, v4.4.36) so a
  typed cohort's dominant base is BaseRepository, but _py_positional_bases
  compared the raw BaseRepository[Shipment] and never matched, firing
  inheritance-convention-violation on every generic repository on every edit --
  the enforcement-side twin of the derivation asymmetry v4.4.36/37 fixed. The
  lint now strips the subscript with the SAME _strip_type_params, and the base
  split is bracket-depth-aware so a multi-arg generic (Generic[T, U]) is not
  fractured on its internal comma. A genuinely wrong base still flags. Verified
  end-to-end: class VehicleRepository(BaseRepository[Vehicle]) in the FastAPI
  fixture no longer fires the rule.

  The bracket-aware comma splitter was de-duplicated in the process: hook_helper
  carried an identical _split_top_level; both now share lint_engine's copy so
  they cannot drift.