Replace argparse with typer for CLI

[sageyu123]

Refactored CLI code to use typer instead of argparse for a cleaner and more user-friendly interface.

Changes

• Rewrote CLI logic using typer.Option and @app.command()
• Updated pyproject.toml with CLI entry points: pyampp, gxbox
• Clarified and improved help messages
• Preserved default values and usage patterns

Benefits

• Cleaner, more readable code
• Built-in help, type validation, and argument parsing
• Easier to extend and maintain
• Existing command usage remains valid. No breaking changes.

Example Usage

gxbox --time "2024-05-12T00:00:00" --coords 0.0 0.0 --hpc