Proper CLI argument parsing

[dannyadair]

This should behave like any regular CLI tool.
help, version, logging verbosity

and then maybe some comfy functions like initialising a new document project.

[dannyadair]

Ok after comparing Click with Typer, I'll go with the more explicit Click for starters (migration - if desired - should be trivial).

• Use logging for internal logic / diagnostics / status.
• Use click.echo() for user-facing messages.

[dannyadair]

Implemented in fe301f4