* fix(backups): prevent recursion in path that is backed up
* fix(share): show user currency instead of the default euro in the share page
* fix(files): show descriptive error for unsupported upload type
Unsupported file uploads showed a generic 'Upload failed' toast even
though the server already returns a descriptive 400. The client catch
blocks discarded the error and always showed t('files.uploadError').
The server now emits the i18n key 'files.uploadErrorType' as its error
message; a new translateApiError() helper resolves a server message that
is a known translation key via t() and falls back to the generic key
otherwise. Wired into the three trip-file upload catch sites.
Closes#1363
819aa793ae