Add Python 3.13 and 3.14 support

[turian]

This PR enables Python 3.13 and 3.14 for aider-chat.

What changed:

• widens requires-python to 3.10 through 3.14
• expands the Ubuntu and Windows workflow matrices to 3.10 through 3.14
• adds marker-based NumPy and SciPy requirements so Python 3.10 stays on older compatible versions while Python 3.11+ can use versions with Python 3.14 wheels
• adds audioop-lts for Python 3.13+ to keep pydub working until upstream support lands

Validation:

• fork CI is green across the expanded matrix, including Python 3.13 and 3.14 on Ubuntu and Windows
• Docker build and pre-commit also passed on the fork

Fork validation PR: turian#1

[CLAassistant]

All committers have signed the CLA.

[paul-gauthier]

Thanks!