Improve serialization compatibility

[mindflayer]

Improved serialization compatibility: ToGo now accepts LinearRing payloads in shape() and supports robust pickle/loky round-trips for geometry sub-objects (e.g., polygon exterior/boundary), reducing multiprocessing deserialization failures.

[Copilot]

Pull request overview

Improves serialization interoperability by making shape() accept GeoJSON-like LinearRing payloads (commonly emitted via __geo_interface__) and adds a dedicated test suite validating pickle and joblib/loky multiprocessing round-trips for core and sub-geometry objects.

Changes:

• Extend shape() to normalize {"type": "LinearRing", ...} payloads into a Ring-derived polygon geometry.
• Add comprehensive multiprocessing/serialization regression tests (pickle + joblib/loky).
• Add joblib to requirements.txt to support the new loky/joblib tests.

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 4 comments.

File	Description
togo.pyx	Updates shape() docs and adds a LinearRing normalization path for GeoJSON-like dict inputs.
tests/test_multiprocessing_serialization.py	Introduces new regression tests covering shape(LinearRing) parsing and pickle/loky round-trips for geometry objects and sub-objects.
requirements.txt	Adds joblib to ensure loky/joblib transfer tests can run in the standard test environment.