feat: Nova UI component library + Studio dropdown/picker polish

- Add Nova UI library: Button, TextInput, Textarea, FormField, Select,
  NovaSelect, Checkbox, Radio/RadioGroup, Toggle, DatePicker,
  DateRangePicker, Modal + barrel index.js
- Replace all native <select> in Studio with NovaSelect (StudioFilters,
  StudioToolbar, BulkActionsBar) including frosted-glass portal and
  category group headers
- Replace native checkboxes in StudioGridCard, StudioTable, UploadSidebar,
  UploadWizard, Upload/Index with custom Checkbox component
- Add nova-scrollbar CSS utility (thin 4px, semi-transparent)
- Fix portal position drift: use viewport-relative coords (no scrollY offset)
  for NovaSelect, DatePicker and DateRangePicker
- Close portals on external scroll instead of remeasuring
- Improve hover highlight visibility in NovaSelect (bg-white/[0.13])
- Move search icon to right side in NovaSelect dropdown
- Reduce Studio layout top spacing (py-6 -> pt-4 pb-8)
- Add StudioCheckbox and SquareCheckbox backward-compat shims
- Add sync.sh rsync deploy script

resources/css/app.css

@@ -63,3 +63,27 @@
   }
 }
 
+@layer utilities {
+  .nova-scrollbar {
+    scrollbar-width: thin;
+    scrollbar-color: rgba(255,255,255,0.14) transparent;
+  }
+  .nova-scrollbar::-webkit-scrollbar {
+    width: 4px;
+    height: 4px;
+  }
+  .nova-scrollbar::-webkit-scrollbar-track {
+    background: transparent;
+  }
+  .nova-scrollbar::-webkit-scrollbar-thumb {
+    background-color: rgba(255,255,255,0.14);
+    border-radius: 999px;
+  }
+  .nova-scrollbar::-webkit-scrollbar-thumb:hover {
+    background-color: rgba(255,255,255,0.28);
+  }
+  .nova-scrollbar::-webkit-scrollbar-corner {
+    background: transparent;
+  }
+}
+