chore: bump version to 0.2.1

[dcruzf]

This pull request transitions the project’s development workflow from using uv and make to using Hatch as the primary tool for dependency management, testing, linting, and publishing. The change is reflected across CI/CD workflows, developer documentation, and project scripts. It also introduces small type safety improvements in the codebase by using cast for array operations, and updates the project version to 0.2.1.

Build and Workflow Modernization:

• Replaces all uv and make-based commands in GitHub Actions workflows (ci.yml, publish.yml, publish-dev.yml) with equivalent Hatch commands, making Hatch the central tool for installation, testing, building, and publishing. [1] [2] [3]
• Removes the Makefile entirely, consolidating all developer and CI tasks under Hatch and updating the .pre-commit-config.yaml to use Hatch commands for formatting, linting, typing, and security checks. [1] [2]
• Updates the README.md with new setup, testing, linting, and security instructions that use Hatch, providing clearer guidance for contributors.

Type Safety and Code Quality:

• Adds explicit cast calls to ensure type safety for numpy array operations in anfis_toolbox/clustering.py, anfis_toolbox/layers.py, anfis_toolbox/losses.py, and anfis_toolbox/membership.py. This helps with static analysis and prevents subtle bugs. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16]
• Minor code cleanups and refactoring for clarity and maintainability, such as renaming variables and removing unnecessary casting in anfis_toolbox/membership.py. [1] [2] [3] [4] [5]

Version Update:

• Bumps the project version to 0.2.1 in anfis_toolbox/__init__.py.