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/js/components/ui/index.js

@@ -0,0 +1,22 @@
+/**
+ * Nova UI Component Library
+ *
+ * Import from this barrel for all standard UI controls:
+ *
+ *   import { Button, TextInput, NovaSelect, DatePicker, ... } from '@/Components/ui'
+ *   // or with path alias:
+ *   import { Button } from '../../Components/ui'
+ */
+
+export { default as Button }          from './Button'
+export { default as TextInput }       from './TextInput'
+export { default as Textarea }        from './Textarea'
+export { default as FormField }       from './FormField'
+export { default as Select }          from './Select'
+export { default as NovaSelect }      from './NovaSelect'
+export { default as Checkbox }        from './Checkbox'
+export { default as Radio, RadioGroup } from './Radio'
+export { default as Toggle }          from './Toggle'
+export { default as DatePicker }      from './DatePicker'
+export { default as DateRangePicker } from './DateRangePicker'
+export { default as Modal }           from './Modal'