✨ feat(vscode): 重写注释排成一队，整个扩展一次只跑一段

OpenPencil 同一时间只能开一个画板，两段同时画会互相掐断。所有预览、所有文件的重写（第一轮和接着说）排成一队，前一段写成、出错、被叫停后按先后自动开始下一段；问 AI 照旧最多同时 3 个。
排着的那一轮记在扩展端（rewriteCurrent 的 queued），块下面写「排队中」、能取消排队，切标签页、页面重新加载后照样显示。

vscode/webview-ui/src/codeReader/useRewrite.ts

@@ -2,21 +2,21 @@ import type { RewriteTree } from './BlockTree'
 import type { ChatState } from './qa'
 import type { ProfileChoice } from './types'
 import { useEffect, useMemo, useReducer, useRef } from 'react'
-import { chatReducer, EMPTY_CHAT, newAskId } from './qa'
+import { chatReducer, EMPTY_CHAT, newAskId, unfinished } from './qa'
 import { toAskImage } from './qaImages'
 import { ANSWER_FRAME_MS } from './useQa'
 import { onMessage, postMessage } from './vscode'
 
 /**
  * 按注释规范重写：收扩展端的重写记录、当前一轮的进展，给块树用的状态和动作。和问 AI 同一套：
- * 进行中的、出错被叫停留着的那一轮记在扩展端，页面重新加载后随 qa 消息的 rewriteCurrent 接上。profile 下拉和问 AI 共用。
+ * 排着队的、进行中的、出错被叫停留着的那一轮记在扩展端，页面重新加载后随 qa 消息的 rewriteCurrent 接上。profile 下拉和问 AI 共用。
  */
 export function useRewrite(profiles: ProfileChoice, onSelectProfile: (id: string) => void): RewriteTree {
   const [state, dispatch] = useReducer(chatReducer<ChatState>, EMPTY_CHAT)
 
   useEffect(() => {
     /** 攒着没画的进展：askId → 最新的一份 */
-    const pending = new Map<string, { question: string, text: string, activity?: string }>()
+    const pending = new Map<string, { question: string, text: string, activity?: string, queued?: boolean }>()
     let timer: ReturnType<typeof setTimeout> | undefined
     const flush = (): void => {
       timer = undefined
@@ -30,7 +30,7 @@ export function useRewrite(profiles: ProfileChoice, onSelectProfile: (id: string
           dispatch({ type: 'sync', available: msg.available, threads: msg.rewrites, current: msg.rewriteCurrent })
           return
         case 'rewriteProgress':
-          pending.set(msg.askId, { question: msg.question, text: msg.text, ...(msg.activity !== undefined && { activity: msg.activity }) })
+          pending.set(msg.askId, { question: msg.question, text: msg.text, ...(msg.activity !== undefined && { activity: msg.activity }), ...(msg.queued && { queued: true }) })
           timer ??= setTimeout(flush, ANSWER_FRAME_MS)
           return
         case 'rewriteEnd':
@@ -45,7 +45,7 @@ export function useRewrite(profiles: ProfileChoice, onSelectProfile: (id: string
     }
   }, [])
 
-  /** 动作里读眼下的状态（这块是不是已经在写） */
+  /** 动作里读眼下的状态（这块是不是已经在写或排着队） */
   const current = useRef(state)
   current.current = state
 
@@ -54,7 +54,7 @@ export function useRewrite(profiles: ProfileChoice, onSelectProfile: (id: string
     profiles,
     onSelectProfile,
     onRewrite: (anchor) => {
-      if (current.current.asks.some(ask => ask.anchor === anchor && ask.status === 'running'))
+      if (current.current.asks.some(ask => ask.anchor === anchor && unfinished(ask)))
         return
       const askId = newAskId()
       // 那句技能命令由扩展端拼好，开始后随 rewriteProgress 报上来