Whitespace in Filenames Causes Issues

Description:
User inputs (e.g., file or folder names) may have leading or trailing spaces, causing unexpected behavior like file not found or duplicate creation.

Expected:
Use .strip() for every user input() to clean up whitespace.

Tasks:

Apply .strip() to all inputs.

Test folder and file creation using spaced inputs.

Find all uses of `input()` in the codebase and apply `.strip()` to the result. Look for file and folder creation functions to test with inputs containing leading/trailing spaces. Run the existing tests or create a simple script to verify the fix prevents duplicate creation and 'file not found' errors.

索引モデルが issue の本文から書いたものです。