[codex] Add autocomplete-friendly type hints

[koaning]

Summary

• Add practical inline type hints to the exported marimo notebook cells and regenerate dicekit/__init__.py.
• Add py.typed packaging metadata so installed editors and marimo language tooling can see the types.
• Add basedpyright type checking for the generated package, matching marimo's documented diagnostics path.
• Fix Dice.from_numbers and add a regression test.

Validation

• make build
• make typecheck
• uv run pytest -q