重构+优化: CR-04+06 AiChat 流式渲染改进 + CR-10 useRendered DRY 抽

- CR-04: splitBlocks 正则切块改 marked.lexer() tokens 遍历(type=code 的 .raw 整块,其余按双换行切),正确处理行首空格/4+反引号嵌套/未闭合围栏——lexer 与 parse 同 marked 实例同 gfm 规则,切块边界与渲染边界一致。
- CR-06: watch(mdReady) 翻 true 时主动 scheduleStreamParse 重算,修首屏 marked 慢+暂无 delta 致末段停留 escapeFallback 纯文本。
- CR-10: useMarkdown 抽 useRendered(computed 读 mdReady+renderMd + ensureLoaded 幂等预热),4 view(TaskDetail/ProjectDetail/Ideas/Knowledge)删手写 renderedDesc computed + onMounted loadMarkdown 重复,loadMarkdown 提模块级。DRY 行为零变化。
批4 wlnazlvdc,vue-tsc 0 err

src/views/ProjectDetail.vue

@@ -241,17 +241,7 @@ import { parseStack } from '../utils/project'
 import { projectStatusLabel, projectStageInfo, taskStatusLabel, taskStatusClass } from '../constants/project'
 import ConfirmDialog from '../components/ConfirmDialog.vue'
 import { useConfirm } from '../composables/useConfirm'
-import { useMarkdown } from '../composables/useMarkdown'
-
-// B-260615-25:项目描述 Markdown 渲染(复用 AiChat/TaskDetail 同款渲染器,模块级单例)
-const { renderMd, loadMarkdown, mdReady } = useMarkdown()
-
-// 描述渲染依赖 mdReady 响应式:loadMarkdown 完成前 escapeFallback 纯文本,完成后 mdReady 翻转
-// 触发 computed 重算(B-25 漏响应式致 v-html=renderMd 首次纯文本后不重算,代码块不渲染)
-const renderedDesc = computed(() => {
-  void mdReady.value
-  return renderMd(currentProject.value?.description ?? '')
-})
+import { useRendered } from '../composables/useMarkdown'
 
 const route = useRoute()
 const router = useRouter()
@@ -280,6 +270,11 @@ const projectId = computed(() => route.params.id as string)
 const currentProject = computed(() =>
   store.projects.find(p => p.id === projectId.value)
 )
+// B-260615-25:项目描述 Markdown 渲染(复用 AiChat/TaskDetail 同款渲染器,模块级单例),
+// useRendered 封装 computed(读 mdReady 触发响应式 + renderMd)+ ensureLoaded(幂等预热)
+const { rendered: renderedDesc, ensureLoaded: ensureMdLoaded } = useRendered(
+  () => currentProject.value?.description ?? '',
+)
 const stageKey = computed(() => currentProject.value?.status ?? 'planning')
 const statusLabel = computed(() => projectStatusLabel(stageKey.value))
 const currentStageIndex = computed(() => projectStageInfo(stageKey.value).stepIndex)
@@ -462,7 +457,7 @@ watch(() => store.pendingApproval, (newApproval) => {
 
 // ── 生命周期 ──
 onMounted(async () => {
-  loadMarkdown() // 后台预热 Markdown 渲染器(模块单例,与 AiChat/TaskDetail 共享),不阻塞
+  ensureMdLoaded() // 后台预热 Markdown 渲染器(模块单例,与 AiChat/TaskDetail 共享),不阻塞
   await store.loadProjects()
   await store.loadTasks() // 全量加载,详情页用 computed 过滤本项目(避免覆盖全局 tasks 单例)
   unlisten = await store.startEventListener()