Option to overwrite existing files on Markdown export

[MateiAmbrus]

Problem:
Joplin currently creates numeric-suffixed files when exporting notes with the same name. This makes it difficult to maintain a clean GitHub repo for selective, iterative publishing.
Proposed Solution:
Add a checkbox or option in export settings:
Overwrite existing files if filename matches

[t0dd]

This may be OS specific. For example, when I export to PDF, my operating system asks me if I want to overwrite the previously exported file. My system is a Fedora 42 Linux desktop. I.e., This may be an OS setting and not a Joplin setting.