fix(chat): 修复滚动回弹和切会话消息异常两处核心bug，附加三项优化 (#425)

Bug 1 — 滚动条/触控板上滚后自动弹回底部
- useStickToBottom.ts: handleScroll 在 isScrolling 期间检测用户上滚方向，
  上滚时立即取消程序化滚动并设 escapedFromLock

Bug 2 — 切回生成中的会话显示"失败"且出现重复空气泡
- ChatConsole.vue: normalizeMessage 加 preserveGeneratingStatus 参数
- ChatConsole.vue: selectConversation 根据 conv.streamStatus 决定是否保留 generating
- ChatConsole.vue: 本地 reconnectStream 移除 isGenerating guard
- useChat.ts: reconnectStream guard 收窄为同会话+正在生成才跳过
- useChat.ts: reconnectStream 复用现有 generating/awaiting_approval 消息

优化1 — hydrateStateFromRoute 路径传 preserveGeneratingStatus=true
优化2 — useStickToBottom 新增 resetLock，MessageList defineExpose，
       selectConversation 切走时调用，避免上滚锁跨会话泄漏
优化3 — reconnect 复用 existingAsst 时清空 contentParts/segments，
       补充 _turnId 确保 flushSegmentsToMessage 正常写入

mateclaw-ui/src/components/chat/MessageList.vue

@@ -186,7 +186,7 @@ const isCronHeader = (msg: Message) => {
 }
 
 // 智能滚动
-const { scrollRef, contentRef, isAtBottom, escapedFromLock, scrollToBottom } = useStickToBottom({
+const { scrollRef, contentRef, isAtBottom, escapedFromLock, scrollToBottom, resetLock } = useStickToBottom({
   enabled: props.autoScroll,
   offset: 70,
   smooth: true,
@@ -275,6 +275,8 @@ function handleGlobalKeydown(e: KeyboardEvent) {
 }
 
 onMounted(() => document.addEventListener('keydown', handleGlobalKeydown))
+defineExpose({ resetScrollLock: resetLock })
+
 onUnmounted(() => {
   clearDockTimer()
   document.removeEventListener('keydown', handleGlobalKeydown)

mateclaw-ui/src/composables/chat/useChat.ts

@@ -2028,7 +2028,7 @@ export function useChat(options: UseChatOptions): UseChatReturn {
 
   // Reconnect to a stream that is already running on the backend
   const reconnectStream = async (conversationId: string) => {
-    if (isGenerating.value) return
+    if (isGenerating.value && streamConversationId === conversationId) return
 
     // Clear any leftover stop fallback timer
     if (stopFallbackTimer) { clearTimeout(stopFallbackTimer); stopFallbackTimer = null }
@@ -2054,9 +2054,28 @@ export function useChat(options: UseChatOptions): UseChatReturn {
       }
     }
 
-    const assistantMessage = createAssistantMessage('', conversationId)
+    const existingAsst = [...messages.value].reverse().find(
-    ;(assistantMessage as any)._turnId = activeTurnId
+      m => m.role === 'assistant'
-    currentAssistantId.value = assistantMessage.id as string
+        && m.conversationId === conversationId
+        && (m.status === 'generating' || m.status === 'awaiting_approval')
+    )
+    if (existingAsst) {
+      updateMessage(existingAsst.id, {
+        ...existingAsst,
+        content: '',
+        contentParts: [],
+        _turnId: activeTurnId,
+        metadata: {
+          ...((existingAsst as any).metadata || {}),
+          segments: [],
+        },
+      } as any)
+      currentAssistantId.value = existingAsst.id as string
+    } else {
+      const assistantMessage = createAssistantMessage('', conversationId)
+      ;(assistantMessage as any)._turnId = activeTurnId
+      currentAssistantId.value = assistantMessage.id as string
+    }
 
     try {
       // reconnectStream always rebuilds from an EMPTY placeholder (above), so it

mateclaw-ui/src/composables/chat/useStickToBottom.ts

@@ -32,6 +32,7 @@ export interface StickToBottomReturn {
   stopScroll: () => void
   /** 检查是否在底部 */
   checkIsAtBottom: () => boolean
+  resetLock: () => void
 }
 
 // 默认配置
@@ -126,12 +127,18 @@ export function useStickToBottom(
   }
 
   // 处理滚动事件
-  const handleScroll = () => {
+ const handleScroll = () => {
-    if (!scrollRef.value) return
+   if (!scrollRef.value) return
-    if (isScrolling) {
+   if (isScrolling) {
+      const currentScrollTop = scrollRef.value.scrollTop
+      if (currentScrollTop < lastScrollTop) {
+        isScrolling = false
+        escapedFromLock.value = true
+        isAtBottom.value = false
+      }
       lastScrollTop = scrollRef.value.scrollTop
       return
-    }
+   }
 
     const element = scrollRef.value
     const currentScrollTop = element.scrollTop
@@ -183,6 +190,11 @@ export function useStickToBottom(
     }, 100)
   }
 
+  const resetLock = () => {
+    escapedFromLock.value = false
+    isAtBottom.value = true
+  }
+
   // ResizeObserver 监听内容变化
   let resizeObserver: ResizeObserver | null = null
 
@@ -245,6 +257,7 @@ export function useStickToBottom(
     scrollToBottom,
     stopScroll,
     checkIsAtBottom,
+    resetLock,
   }
 }
 

mateclaw-ui/src/views/ChatConsole.vue

@@ -1483,7 +1483,7 @@ async function hydrateStateFromRoute() {
       try {
         const res: any = await conversationApi.listMessages(conversationId)
         if (currentConversationId.value !== conversationId) return
-        messages.value = extractMessages(res).messages.map((msg: Message) => normalizeMessage(msg))
+      messages.value = extractMessages(res).messages.map((msg: Message) => normalizeMessage(msg, true))
       } catch {
         // 消息加载失败，保持空
       }
@@ -1522,6 +1522,7 @@ async function selectConversation(conv: Conversation) {
   const switchingAway = currentConversationId.value !== conv.conversationId
   if (switchingAway) {
     resetForNewConversation()
+    messageListRef.value?.resetScrollLock()
   }
   currentConversationId.value = conv.conversationId
   selectedAgentId.value = conv.agentId || selectedAgentId.value
@@ -1544,7 +1545,8 @@ async function selectConversation(conv: Conversation) {
     if (currentConversationId.value !== requestedConvId) return
     // 点同一个会话时，若已有 SSE 在跑就不要覆盖本地消息状态
     if (switchingAway || !isGenerating.value) {
-      messages.value = extractMessages(res).messages.map((msg: Message) => normalizeMessage(msg))
+      const convRunning = conv.streamStatus === 'running'
+      messages.value = extractMessages(res).messages.map((msg: Message) => normalizeMessage(msg, convRunning))
     }
 
     // Hydrate pending approvals：恢复刷新后丢失的审批卡片（RFC-067 §4.9）
@@ -1943,7 +1945,6 @@ async function handleApproveAlways(
 
 // 重连到运行中的流
 async function reconnectStream(conversationId: string) {
-  if (isGenerating.value) return
   try {
     await reconnectChatStream(conversationId)
   } catch (e) {
@@ -2037,7 +2038,7 @@ function buildOutgoingParts(text: string, attachments: ChatAttachment[]): Messag
 }
 
 // ============ 工具函数 ============
-function normalizeMessage(raw: Message): Message {
+function normalizeMessage(raw: Message, preserveGeneratingStatus?: boolean): Message {
   const msg: Message = { ...raw, contentParts: raw.contentParts ? [...raw.contentParts] : [] }
 
   // 统一解析 metadata：确保是对象而非 JSON 字符串
@@ -2107,7 +2108,7 @@ function normalizeMessage(raw: Message): Message {
     msg.metadata = { ...msg.metadata, toolCalls: cleaned }
   }
 
-  if (msg.status === 'generating') msg.status = 'failed'
+  if (!preserveGeneratingStatus && msg.status === 'generating') msg.status = 'failed'
   // interrupted 是合法的历史状态（interrupt-with-followup），不映射为 stopped
   if (!msg.status) msg.status = 'completed'