Update requirements, make keras-hub optional for 3.13+

[nikolasavic3]

• Python >= 3.11 is now required because flax 0.11.1 and above only support Python 3.11 or newer.
• Add platform and Python version markers for keras-hub and jax_tpu_embedding to avoid install issues on unsupported systems.
• Update scikit-learn to allow >=1.6.1.
• Add pytest skip for keras_hub tests on Python 3.13+ (Update dev dependencies to Python 3.13 #115)
• Add explicit strict=False to all zip() calls to address ruff warnings.