SIM intake with carrier box limits and a scan queue

SIM receiving enforces each carrier's box size and queues scans until you confirm, rejecting duplicates.

SIMs arrive in boxes of a fixed size for each carrier. Intake now enforces those sizes, 10 per box for AT&T and Verizon and 50 for T-Mobile, and keeps scanned SIMs in a queue until you click Receive.

Duplicate scans are rejected, so each SIM is received once.