[DEV] [PLUGIN] [FINAL] Add Error Messages For Non Python Inputs

[mmyaaaaa]

The tool shall gracefully handle unexpected inputs, such as invalid code or non-
Python files.

Rationale: Ensuring stability with error handling prevents tool crashes and
improves user experience.

Fit Criterion: The tool should provide clear error messages and recover from
input errors without crashing, ensuring stability.

Priority: High