Suggestion: Modify Plugin Behavior to Add Converted ePub as a separate File instead of modifying Original

[alpakadev]

Currently, when you use this Calibre Plugin to convert ePub files, it changes the original ePub by overwriting it and saving a backup with a .original_epub extension.

Issue #3 suggests that users should be warned about this irreversible change before converting.

Here's my suggestion: Instead of messing with the original ePub, why not just add the converted file next to it? This way, users have more freedom and don't have to worry about losing the integrity of the original version. They can convert files without stressing about losing anything, and they still have access to both versions.