Audit PRs #920 (printers search/filter) and #932 (print from project
view) for regressions, i18n coverage, test gaps, and docs.
No regressions found: existing callers of the changed signatures
(archive_print, getLibraryFiles, filteredPrinters chain) are unaffected;
i18n is complete in all 7 locales for both features.
Backend tests (4 new, all passing):
- test_list_files_by_project_id — bulk JOIN returns files across all
linked folders, excludes unlinked ones
- test_list_files_folder_id_takes_precedence_over_project_id — guards
the documented precedence folder_id > project_id > include_root
- test_add_to_queue_with_project_id — project_id is persisted on the
queue row for later archive linkage
- test_add_to_queue_invalid_project_id_returns_404 — regression guard
for the validation pre-check on the queue path (mirrors the one on
the direct-print path in library.py)