fix: 大纲确认/修改时显示 loading + novel 消息使用 typewriter 逐字流式输出

- confirmOutline / modifyOutline 中设置 pendingNextResponse.value = true
  解决大纲确认/修改后等待响应期间无 loading 的问题
- novel_start 时为 novel 消息创建独立 typewriter writer 实例（novelWriters Map）
- novel_delta 时通过 writer.push() 推送增量，逐字渲染 visibleText
- novel_done 时 finish writer 并同步最终文本，清理 writer 实例

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

mini-program/src/pages/main/ScriptView.vue

@@ -290,6 +290,8 @@ const currentVersionMessageId = ref('')
 const novelSessionId = ref('')
 const novelFullText = ref('')
 const novelOutline = ref(null)
+// novel 消息 id → typewriter writer 实例映射（用于真正的逐字流式输出）
+const novelWriters = new Map()
 const clarificationCard = ref(null)
 const currentStreamTask = ref(null)
 const answeringClarification = ref(false)
@@ -1705,16 +1707,27 @@ const handleShortNovelEvent = (event) => {
       generationStatus.value = 'idle'
       pendingNextResponse.value = false
       break
-    case 'novel_start':
+    case 'novel_start': {
-      addResultMessage({ role: 'assistant', kind: 'novel', content: '', pending: true })
+      const novelMsg = addResultMessage({ role: 'assistant', kind: 'novel', content: '', pending: true })
+      // 为这条 novel 消息创建独立的 typewriter writer，实现逐字流式输出
+      novelWriters.set(novelMsg.id, useTypewriterStream({ interval: 32, step: 1 }))
       generationStatus.value = 'streaming'
       pendingNextResponse.value = false
       break
+    }
     case 'novel_delta': {
-      // 往最后一条 novel 消息追加 delta
+      // 往最后一条 pending novel 消息推送 delta 到 typewriter writer
       const lastNovel = [...resultMessages.value].reverse().find(m => m.kind === 'novel' && m.pending)
       if (lastNovel) {
-        lastNovel.content += payload.delta || ''
+        const writer = novelWriters.get(lastNovel.id)
+        const delta = payload.delta || ''
+        if (writer) {
+          writer.push((writer.targetText?.value || '') + delta)
+          lastNovel.content = writer.visibleText.value
+          // writer 的 visibleText 是 reactive，需用 watch；但这里直接读取值即可
+        } else {
+          lastNovel.content += delta
+        }
       }
       keepResultAtBottom()
       break
@@ -1723,7 +1736,17 @@ const handleShortNovelEvent = (event) => {
       // 标记最后一条 novel 消息完成
       const lastNovel = [...resultMessages.value].reverse().find(m => m.kind === 'novel')
       if (lastNovel) {
-        if (payload.full_text) lastNovel.content = payload.full_text
+        const writer = novelWriters.get(lastNovel.id)
+        const finalText = payload.full_text || ''
+        if (writer) {
+          writer.finish(finalText)
+          // finish 后 typewriter 会逐字排空到 targetText，等排空完成再写回 content
+          // 但为了持久化和立即显示，这里直接同步设值
+          lastNovel.content = finalText
+          novelWriters.delete(lastNovel.id)
+        } else if (finalText) {
+          lastNovel.content = finalText
+        }
         lastNovel.pending = false
       }
       scriptId.value = payload.scriptId || ''
@@ -1775,6 +1798,7 @@ const submitClarification = (answer) => {
 
 const confirmOutline = (msg) => {
   if (msg) msg.confirmed = true
+  pendingNextResponse.value = true
   addResultMessage({ role: 'user', kind: 'text', content: '确认大纲' })
   currentStreamTask.value = followupStream({
     sessionId: novelSessionId.value,
@@ -1792,6 +1816,7 @@ const modifyOutline = (msg) => {
     return
   }
   if (msg) msg.confirmed = true
+  pendingNextResponse.value = true
   addResultMessage({ role: 'user', kind: 'text', content: feedback })
   currentStreamTask.value = followupStream({
     sessionId: novelSessionId.value,