Add Type Hinting for Arguments & Returns

[ashleyshaw]

Description
Implement argument and return type hints in functions and methods to enhance code clarity and prevent type-related errors.

Why This Matters

• Type hinting helps developers understand expected input/output.
• Reduces runtime errors and strengthens code maintainability.

Tasks

1. Audit existing classes and functions for potential type hinting.
2. Gradually add typed arguments and return statements.
3. Update or add tests to confirm no new fatal errors occur.