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/Knowledge.vue

@@ -235,22 +235,12 @@
 import { ref, computed, onMounted, watch } from 'vue'
 import { useI18n } from 'vue-i18n'
 import { useKnowledgeStore, KNOWLEDGE_KINDS, parseTags } from '../stores/knowledge'
-import { useMarkdown } from '../composables/useMarkdown'
+import { useRendered } from '../composables/useMarkdown'
 import type { KnowledgeDetailPayload, KnowledgeEventRecord } from '../api/types'
 
 const { t } = useI18n()
 const store = useKnowledgeStore()
 
-// B-260615-25:知识内容 Markdown 渲染(复用 AiChat/TaskDetail 同款渲染器,模块级单例)
-const { renderMd, loadMarkdown, mdReady } = useMarkdown()
-
-// 内容渲染依赖 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 renderedContent = computed(() => {
-  void mdReady.value
-  return renderMd(detail.value?.knowledge.content ?? '')
-})
-
 // 顶层 Tab: library(知识库) | inbox(审核收件箱)
 const topTab = ref<'library' | 'inbox'>('library')
 
@@ -309,6 +299,11 @@ function getCategoryCount(key: string): number {
 // ===== 详情选中 + 加载 =====
 const selectedId = ref<string | null>(null)
 const detail = ref<KnowledgeDetailPayload | null>(null)
+// B-260615-25:知识内容 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: renderedContent, ensureLoaded } = useRendered(
+  () => detail.value?.knowledge.content ?? '',
+)
 const refLimit = ref(10)
 
 async function selectKnowledge(id: string) {
@@ -512,7 +507,7 @@ function relativeTime(millisStr: string): string {
 }
 
 onMounted(() => {
-  loadMarkdown() // 后台预热 Markdown 渲染器(模块单例,与 AiChat/TaskDetail 共享),不阻塞
+  ensureLoaded() // 后台预热 Markdown 渲染器(模块单例,与 AiChat/TaskDetail 共享),不阻塞
   store.loadList()
   store.loadCandidates()
 })