fix(fusion_clock): Photo Verification is now a real master switch (was ignored)

The global enable_photo_verification toggle only fed the portal get_settings flag;
the actual writes ignored it — the NFC kiosk gated on nfc_photo_required and the
portal on location.require_photo, so photos were captured even with the toggle OFF.
Now it's the master: OFF => no photo captured/stored anywhere (NFC kiosk config +
tap, and portal check-in); ON => per-location / NFC settings apply. Test + help
text updated. Bump 3.16.0 -> 3.16.1.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

fusion_clock/models/res_config_settings.py

@@ -136,7 +136,9 @@ class ResConfigSettings(models.TransientModel):
     fclk_enable_photo_verification = fields.Boolean(
         string='Enable Photo Verification',
         default=False,
-        help="Global toggle for selfie verification on clock-in (per-location control).",
+        help="Master switch for selfie capture. When OFF, no photos are taken on "
+             "any clock-in/out (portal or NFC kiosk). When ON, the per-location and "
+             "NFC-kiosk photo settings apply.",
     )
     fclk_google_maps_api_key = fields.Char(
         string='Google Maps API Key',