Introduce Hatch-managed environments to the project

[candleindark]

Summary

Introduce Hatch-managed environments to the project.

• Adds [tool.hatch.envs.default] section to pyproject.toml
• Sets uv as the installer for the default Hatch environment
• Pins the default Python version to 3.10

Test plan

• Verify hatch env create uses uv as the installer

TODOs

• This PR is based on Consolidate package metadata from setup.py/setup.cfg into pyproject.toml #379. To get the relevant commits in this PR rebase on master after Consolidate package metadata from setup.py/setup.cfg into pyproject.toml #379 is merged to master.
• This PR should be merged after Consolidate package metadata from setup.py/setup.cfg into pyproject.toml #379 is merged to master.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.91%. Comparing base (3725ccc) to head (6c45c52).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #380   +/-   ##
=======================================
  Coverage   97.91%   97.91%           
=======================================
  Files          18       18           
  Lines        2401     2401           
=======================================
  Hits         2351     2351           
  Misses         50       50           

Flag	Coverage Δ
unittests	97.91% <ø> (ø)

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