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>

frontends/ui/src/Input.tsx

@@ -0,0 +1,50 @@
+import type { InputHTMLAttributes, TextareaHTMLAttributes } from 'react'
+import type { IconComponent } from './Icons'
+
+interface InputProps extends Omit<InputHTMLAttributes<HTMLInputElement>, 'onChange'> {
+  value: string
+  onChange: (value: string) => void
+  Icon?: IconComponent
+}
+
+interface TextareaProps extends Omit<TextareaHTMLAttributes<HTMLTextAreaElement>, 'onChange'> {
+  value: string
+  onChange: (value: string) => void
+  rows?: number
+}
+
+export function Input({ value, onChange, Icon, className = '', ...props }: InputProps) {
+  if (Icon) {
+    return (
+      <div className="relative">
+        <Icon className="absolute left-3 top-1/2 -translate-y-1/2 text-muted text-sm" />
+        <input
+          className={`input pl-9 ${className}`}
+          value={value}
+          onChange={e => onChange(e.target.value)}
+          {...props}
+        />
+      </div>
+    )
+  }
+  return (
+    <input
+      className={`input ${className}`}
+      value={value}
+      onChange={e => onChange(e.target.value)}
+      {...props}
+    />
+  )
+}
+
+export function Textarea({ value, onChange, rows = 4, className = '', ...props }: TextareaProps) {
+  return (
+    <textarea
+      className={`input resize-none ${className}`}
+      value={value}
+      onChange={e => onChange(e.target.value)}
+      rows={rows}
+      {...props}
+    />
+  )
+}