build: convert setup.py to pyproject

[RecRanger]

Overview

This PR converts the old, legacy setup.py build configuration to a modern pyproject.toml file.

It also converts the build system from setuptools to hatchling (the secure, simpler, modern alternative).

It brings all other settings over, exactly as they are.

Types of changes

• Refactor/enhancement
• Bug fix/behavior correction
• New feature
• Breaking change
• Other, additional

Notes

Simple change.

Status

• Prefix PR title with [WIP] if necessary (changes not yet made).
• Add tests to cover changes as needed.
• Update documentation/changelog as needed.
• Verify all tests run correctly in CI and pass.
• Ready for review/merge.

---

Note

Medium Risk
Low functional risk to runtime code, but it changes the packaging/build backend from setuptools to hatchling, which can impact how wheels/sdists are built and published.

Overview
Migrates project packaging from legacy setup.py to a PEP 621 pyproject.toml, switching the build backend to hatchling.

Carries over the existing project metadata and runtime dependencies, adds a dev dependency group, and configures wheel builds to include the py_clob_client package.

^{Written by Cursor Bugbot for commit 461e17c. This will update automatically on new commits. Configure here.}