Detailed-mode research reports now honor the ``report.enable_file_backup`` setting. The detailed completion path saved ``report_content`` via a raw ORM write that bypassed the report-storage abstraction, so a user who enabled file backup got on-disk ``.md``/``_metadata.json`` files for quick-mode research but silently never for detailed-mode research. Route the detailed save through ``get_report_storage().save_report()`` exactly like the quick and error paths already do (DRY-review finding H2).
