Relax Python version requirement to >=3.10

[MaxGhenis]

Summary

• Changes requires-python from >=3.13,<3.14 to >=3.10,<3.14

Fixes #1493

Context

The >=3.13 requirement was unintentionally set when migrating from setup.py (which had >=3.7) to pyproject.toml. This aligns with policyengine-us which uses >=3.10,<3.14.

Test plan

• CI passes on Python 3.10, 3.11, 3.12, 3.13

[MaxGhenis]

Closing as obsolete. The repo has since moved in the opposite direction: current pyproject.toml requires Python 3.13, so relaxing to >=3.10 is no longer aligned with mainline support.