refactor: move studio to frontends workspace

- Move studio from root to frontends/studio/
- Add owner-tools frontend for live blog admin UI
- Add shared ui component library
- Set up npm workspaces for frontends
- Add enhanced code block extension for editor

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

studio/src/components/ui/Select.tsx

@@ -1,33 +0,0 @@
-interface SelectOption {
-  value: string
-  label: string
-}
-
-interface SelectProps {
-  value: string
-  onChange: (value: string) => void
-  options: SelectOption[]
-  placeholder?: string
-  className?: string
-}
-
-export function Select({ value, onChange, options, placeholder, className = '' }: SelectProps) {
-  return (
-    <select
-      value={value}
-      onChange={e => onChange(e.target.value)}
-      className={`input ${className}`}
-    >
-      {placeholder && (
-        <option value="" disabled>
-          {placeholder}
-        </option>
-      )}
-      {options.map(opt => (
-        <option key={opt.value} value={opt.value}>
-          {opt.label}
-        </option>
-      ))}
-    </select>
-  )
-}