fix(encryption): refactor/improve DecryptAll/EncryptAll robustness/error handling

[joshtrichards]

• Resolves: #

Summary

Changes

• Improved logic to ensure only files owned by the user are decrypted, preventing changes to shared or group data.
• More robust error handling: file operation failures now raise exceptions and are properly logged.
• Progress messages and logs are clearer and more informative.
• Refactoring enhances code readability and maintainability.
• Clean-up routines now reliably remove temp files after errors.
• Return values explicitly distinguish between actions performed and files skipped.
• Aligned the implementations of EncryptAll and DecryptAll more closely (still not perfect)

Benefits

Safer decryption for user data, enhanced reliability, and easier ongoing maintenance.

TODO

• Update tests
• Decide whether to do any of the inline TODOs while we're here
• Double-check the UI output experience

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)