fix(web): 写作台流式/保存 live region + 图标按钮换 lucide 无障碍 + 三栏改 xl 断点 + 手稿字号统一

apps/web/components/workbench/Editor.tsx

@@ -2,6 +2,8 @@
 
 import { useEffect, useRef } from "react";
 
+import { cn, focusRing, proseBody } from "@/lib/ui/variants";
+
 interface EditorProps {
   value: string;
   onChange: (value: string) => void;
@@ -36,7 +38,11 @@ export function Editor({ value, onChange, streaming }: EditorProps) {
         readOnly={streaming}
         aria-busy={streaming}
         placeholder="夜色如墨……点击「写本章」让 AI 起草，或直接在此书写。"
-        className="block min-h-[60vh] w-full resize-none overflow-hidden bg-transparent font-serif text-[18px] leading-[1.9] text-ink placeholder:text-ink-soft/50 focus:outline-none"
+        className={cn(
+          proseBody,
+          "block min-h-[60vh] w-full resize-none overflow-hidden rounded bg-transparent text-ink placeholder:text-ink-soft/50",
+          focusRing,
+        )}
       />
       {streaming ? (
         <span