Improve receptionist screen & registration wizard mobile UX

Dashboard:
- Primary action (new registration) is now a full-width hero card
- Secondary actions are a compact 2x2 icon grid

Registration wizard:
- Mobile step indicator: compact progress bar + step name instead of
  cramped 5-circle stepper
- Sticky bottom nav bar on mobile (fixed position, safe-area aware)
  so Back/Next are always reachable without scrolling
- Activity selection uses horizontal scrollable pills on mobile
- Desktop layout remains unchanged (sm: breakpoint gates all changes)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

resources/css/app.css

@@ -181,6 +181,13 @@ hover:border-cyan-300 hover:border-pink-300 hover:border-orange-300 hover:border
         transform: scale(0.95) !important;
         opacity: 0.9;
     }
+    .scrollbar-hide {
+        -ms-overflow-style: none;
+        scrollbar-width: none;
+    }
+    .scrollbar-hide::-webkit-scrollbar {
+        display: none;
+    }
 }
 
 /* Print: hide all app chrome */