fix(fusion_clock): hide the Odoo backend escape hatch on the NFC kiosk

The website module injects a fixed "frontend->backend" nav
(.o_frontend_to_backend_nav — the floating apps-grid/edit button) on every
frontend page for any internal user. Since the kiosk account is an internal
user, that button let a kiosk user tap through to the Odoo backend.

Hide it with a page-scoped inline style in the kiosk template head, so it's
suppressed only on /fusion_clock/kiosk/nfc and the real website keeps its nav.

Live as 19.0.3.11.8 (verified the rule is in the rendered template).

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

fusion_clock/views/kiosk_nfc_templates.xml

@@ -14,6 +14,11 @@
                 <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent"/>
                 <meta name="apple-mobile-web-app-title" content="Fusion Clock Kiosk"/>
                 <link rel="apple-touch-icon" href="/fusion_clock/static/description/icon.png"/>
+                <!-- Kiosk lockdown: hide Odoo's frontend->backend nav (the floating
+                     "Go to your Odoo Apps" / edit button the website module injects for
+                     logged-in internal users) so a kiosk user can't reach the backend.
+                     Page-scoped here so the real website keeps its nav. -->
+                <style>.o_frontend_to_backend_nav { display: none !important; }</style>
             </t>
 
             <div id="nfc_kiosk_root" class="nfc-kiosk"