[Python] Release 0.47.0

Added

• Free-threaded wheels for Python 3.15 (3.15t).
• Optional iter_errors(instance) method on custom keyword validators for reporting multiple errors from a single keyword. #1071

Changed

• Update pyo3 to 0.29.
• Clearer import error on free-threaded Python when older pip installs the abi3 wheel. #1131

Performance

• Faster validator construction, via compile-time meta-schema validators.

Fixed

• type under items asserted with the Validation vocabulary disabled.
• Disabled vocabularies ignored for $ref targets without their own $schema (e.g. $defs entries).

Removed

• Support for Python 3.13t following the pyo3 update.