fix: clean up empty parent category directory on script deletion

[tejask011]

Fixes Issue #231

Description

This pull request resolves the issue where deleting a script left behind an empty category directory on the local filesystem.

Previously, when the last script within a category was deleted, the script file was removed successfully but the now-empty category directory remained under the scripts/ directory. Over time, this could lead to an accumulation of unused empty folders.

With this change, the application now automatically checks the parent category directory after a script deletion. If the directory is empty and is not the root scripts/ directory, it is removed automatically.

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Changes Made

Backend Changes

• Updated the script deletion workflow to perform automatic cleanup of empty category directories.
• Added safeguards to ensure the root scripts/ directory is never removed.
• Preserved existing path validation and security checks.

Test Updates

• Added test coverage for automatic cleanup of empty category folders.
• Added test coverage to ensure category folders are retained when other scripts still exist.
• Verified existing deletion-related tests continue to pass.

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Testing and Validation

Scenarios Tested

1. Delete Last Script in a Category

• Created a category containing a single script.
• Deleted the script.
• Verified the script file was removed.
• Verified the empty category directory was automatically deleted.

2. Delete Script While Other Scripts Exist

• Created a category containing multiple scripts.
• Deleted one script.
• Verified the script file was removed.
• Verified the category directory remained intact because other scripts still existed.

3. Regression Testing

• Executed the complete test suite.
• Confirmed all existing tests continue to pass without modification.

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Screenshots and Logs

No UI changes were introduced as part of this fix.

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Checklist

• No breaking changes
• Tests added or updated
• Existing tests pass successfully
• Documentation updated where necessary
• Branch is up to date with main
• Root scripts/ directory remains protected

##close #231