✨ 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/BlockTree.tsx

@@ -14,7 +14,7 @@ import { DiffText } from './DiffText'
 import { removedTitle } from './diffView'
 import { KindIcon } from './kindIcons'
 import { PropertyGrid, PropertyTable } from './PropertyGrid'
-import { asksOf, historyOf } from './qa'
+import { asksOf, historyOf, unfinished } from './qa'
 import { TextPreview } from './TextPreview'
 import { tableId } from './viewState'
 
@@ -272,7 +272,7 @@ function callTreeTool(block: BlockView, tree: BlockTreeState) {
 
 /**
  * 这块的「重写注释」按钮：能写注释的块才有。重写过、记录收着时点了先展开记录（好接着说）；展开着、或还没重写过时点了按技能命令重写。
- * 展开着又正在写时不能再点。
+ * 展开着又正在写、排着队时不能再点。
  */
 function rewriteTool(block: BlockView, tree: BlockTreeState): RewriteTool | undefined {
   const { edit, rewrite } = tree
@@ -284,7 +284,7 @@ function rewriteTool(block: BlockView, tree: BlockTreeState): RewriteTool | unde
   const reopen = !open && (asks.length > 0 || historyOf(rewrite.state, anchor).length > 0)
   return {
     fresh: block.commentTarget.kind === 'insert',
-    rewriting: open && asks.some(ask => ask.status === 'running'),
+    rewriting: open && asks.some(unfinished),
     reopen,
     onRewrite: () => reopen ? rewrite.onOpen(anchor) : rewrite.onRewrite(anchor),
   }