Add comprehensive type stubs to improve Python import

[TrevisGordan]

I did some improvements on typing support:

• Add complete type stubs (.pyi files) for all classes and exceptions with proper type annotations
• Fix import recognition in IDEs through explicit __all__ list and py.typed marker
• Add module documentation in Rust that inherits to Python for better help() output

Fixes:

• ✅ IDE autocompletion and type checking now work correctly
• ✅ from vodozemac import Account, PickleException properly recognized

[PaarthShah]

Tentatively looks good! I'd gotten about halfway on this before getting distracted; I'm gonna test out a few potential simplifications soon locally just in case, but I think this is probably mostly good