Fix: Use FileNotFoundError for file not found in main.py

[creepereye1204]

Replaced IOError with FileNotFoundError on line 320 of main.py to use a more specific and appropriate exception for file not found errors.

[creepereye1204]

Title: Refactor: Improve error handling and remove unused parameter in main.py

Description:

This pull request introduces two refactoring changes to main.py aimed at improving code clarity and maintainability.

1. Use Specific Exception for File Not Found:
   The code previously raised a general IOError when a file was not found. This has been updated to raise the more specific FileNotFoundError. This change provides clearer error information to callers and allows for more precise error handling.

   Before (approx. line 319):

   if raise_error_if_not_found:
       raise IOError("File not found")
   return ""

   After:

   if raise_error_if_not_found:
       raise FileNotFoundError("File not found")
   return ""