/api/system/status now returns a best-effort storage block: database file size
(crm.db + WAL + SHM), the email_attachments dir, the backups dir, and disk
total/used/free via shutil.disk_usage(DATA_DIR). System Status renders a Storage
section with human-readable sizes so growth can be watched over time.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>