Adds /fusion_clock/kiosk/nfc/enroll (jsonrpc, auth=user) that validates
the enroll password, normalises the card UID, checks for duplicate
assignments, writes x_fclk_nfc_card_uid, and creates a card_enrollment
activity log entry. 4 new tests; 21 total passing.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Add _normalize_uid static method to FusionClockNfcKiosk that strips
whitespace, uppercases, removes separators, validates hex-only content,
and reformats to canonical colon-separated pairs; returns None for
empty/invalid input. Covered by 7 new TransactionCase unit tests.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
