Add support through python3.14. Move to pyproject.toml. Fix deprecated locale function.

[brandonschabell]

Creating a PR to address a few issues:

• Adding support through python 3.14
• Moving most of the setup.py metadata to pyproject.toml.
• Fix deprecation warning related to the locale.getdefaulelocale() function (replaced with locale.getlocale() + a try/except block in case there's an unexpected failure.

[Copilot]

Pull Request Overview

This PR modernizes the package configuration by migrating from a legacy setup.py to the modern pyproject.toml standard, fixing a deprecated locale API call, and updating Python version support.

• Migrated package metadata and dependencies from setup.py to pyproject.toml (PEP 621 compliance)
• Replaced deprecated locale.getdefaultlocale() with locale.getlocale() and added exception handling
• Added Python 3.11-3.14 support in documentation and CI workflows

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
setup.py	Simplified to minimal custom commands; moved metadata to pyproject.toml
pyproject.toml	Added comprehensive project metadata, dependencies, and dynamic version configuration
ccimport/buildtools/writer.py	Fixed deprecated locale API call with exception handling
ccimport/init.py	Added version import with fallback and all definition
test/test_source_iter.py	Changed return statement to assertion (test fix)
README.md	Updated Python version support documentation to 3.6-3.14
.github/workflows/build.yaml	Added Python 3.11-3.14 to CI test matrix

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.