feat(fusion_clock): NFC card UID normalization helper

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>

fusion_clock/controllers/clock_nfc_kiosk.py

@@ -3,15 +3,32 @@
 # License OPL-1 (Odoo Proprietary License v1.0)
 
 import logging
+import re
 from odoo import http
 from odoo.http import request
 
 _logger = logging.getLogger(__name__)
+_UID_HEX_PATTERN = re.compile(r'^[0-9A-F]+$')
 
 
 class FusionClockNfcKiosk(http.Controller):
     """NFC tap-to-clock kiosk controller. Reuses FusionClockAPI helpers."""
 
+    @staticmethod
+    def _normalize_uid(uid):
+        """Normalize an NFC card UID to canonical hex (uppercase, colon-separated).
+
+        Returns None if the input is empty or not valid hex.
+        """
+        if not uid:
+            return None
+        cleaned = uid.strip().upper().replace('-', '').replace(':', '').replace(' ', '')
+        if not cleaned or not _UID_HEX_PATTERN.match(cleaned):
+            return None
+        if len(cleaned) % 2 != 0:
+            return None
+        return ':'.join(cleaned[i:i+2] for i in range(0, len(cleaned), 2))
+
     @http.route('/fusion_clock/kiosk/nfc', type='http', auth='user', website=True)
     def nfc_kiosk_page(self, **kw):
         """Render the NFC kiosk page for a wall-mounted tablet."""