Submit Qc Signoff

QC sign-off on a RECEIVED item.

Body: condition: 'good' | 'damaged' | 'wrong_item' | 'short' | 'other' (required) inspector_name: str (required, typed name) signature: str (required, base64 PNG) notes: str (optional) approve: bool (default true; always pushes to inventory) flag_for_resolution: bool (optional; recorded on the qc_log entry as a damage flag — purely a record for now, does not itself gate the notification below)

Any condition other than 'good' dispatches a qc_flagged notification to shop admins (shop_role_ids=[1, 3]) — see _notify_shop_admins — deep-linking to the item's expanded row in Inventory.