[FEATURE REQUEST] Export files from scoped storage

After scope storage is already in, we can provide users a way to reach the files in the device (out of oC) beyond the document provider. Many feedback about getting the files was received, so, this option could be interesting for users of apps that do not implement the document provider (recommended option).

Ideas about it (ACs draft)

• Exported files will be a copy out of oC. Those copies will not synced anymore.
• Available for files and folders (with recursivity. Enough memory? -> no crash)
• New option in three-dot-button, called Export. Also available in the multiselection menu. Check for the best icon "ifRoom"
• Available in preview mode
• If selected file is not downloaded, it will be downloaded to be exported (could it be removed afterwards?). Check if it is feasible to download directly in target folder, chosen by the user.
• The option will show a folder picker to select the target -> system.
• Conflict handling, out of oC? (f.ex. exporting a file to a folder which contains a file with the same name)
  • Copy recursively: only override/no override (keep original copy)
  • Do it manually

More ideas and feedback is welcome

TASKS

• Research (if needed)
• Create branch feature/feature_name
• Development tasks
  • Implement whatever
  • ...
• Code review and apply changes requested
• Design test plan
• QA
• Merge branch feature/feature_name into master

PR

• App
• Library (if needed)

No files, tests, or entry points are named. Start by reviewing the existing scoped-storage and document-provider flows, then clarify the unresolved choices around recursive folders, downloads, conflicts, and memory use. Done means the export entry points and folder picker behavior are defined for files, folders, preview mode, and multiselection, with a test plan.