perf(web): 子代理 stream_delta rAF 批处理 + 消息槽 memo 化 + base64 分块解码

- useSubAgentView 镜像主视图：delta 累加到 ref，rAF 批量一次 setState，避免逐 token 重渲染
- 所有非 delta 消息处理前同步落盘 pending delta，保证顺序与内容完整性
- MessageList 消息 ID 映射 useMemo，稳定回调引用减少重渲染
- MessageBubble base64 下载改分块解码（32K），大附件峰值内存从数百 MB 降为单块级

web/src/App.tsx

@@ -423,6 +423,16 @@ function App() {
     sendMessage({ type: 'command', payload: JSON.stringify(cmd) });
   }, [sendMessage, handleCommand, handleStop]);
 
+  // 稳定引用：只读视图（子智能体/定时任务）下的空发送回调，
+  // 避免内联箭头函数每次渲染产生新引用、破坏下游 memo 化。
+  const noopSendMessage = useCallback(() => {}, []);
+
+  // 稳定引用：打开专家设置页
+  const openExpertsSettings = useCallback(() => {
+    setConfigInitialTab('experts');
+    setConfigPageOpen(true);
+  }, []);
+
   const handleCreateTopic = useCallback(() => {
     if (isReadOnly || !sessionId) {
       return;
@@ -1007,7 +1017,7 @@ function App() {
                       channels.find((c) => c.id === selectedChannel)?.name ??
                       'PicoBot')
               }
-              onSendMessage={subAgentView || schedulerView ? () => {} : handleSendMessage}
+              onSendMessage={subAgentView || schedulerView ? noopSendMessage : handleSendMessage}
               onNavigateToSubAgent={handleNavigateToSubAgent}
               onStop={handleStopExecution}
               showThinking={showThinking}
@@ -1015,10 +1025,7 @@ function App() {
               highlightedMessageId={highlightedMessageId}
               sessionId={sessionId}
               settingsClosedTick={settingsClosedTick}
-              onOpenSettings={() => {
+              onOpenSettings={openExpertsSettings}
-                setConfigInitialTab('experts');
-                setConfigPageOpen(true);
-              }}
             />
           </div>
         </div>

web/src/components/Chat/ChatContainer.tsx

@@ -1,4 +1,4 @@
-import { useState } from 'react';
+import { useState, useCallback } from 'react';
 import { MessageList } from './MessageList';
 import { MessageInput } from './MessageInput';
 import { ExpertSelector } from './ExpertSelector';
@@ -55,6 +55,13 @@ export function ChatContainer({
     model: string;
   } | null>(null);
 
+  // 稳定引用，避免内联箭头破坏下游 memo 化
+  const handleModelSelectionChange = useCallback(
+    (effective: { provider: string; model: string }) =>
+      setEffectiveModel({ provider: effective.provider, model: effective.model }),
+    [],
+  );
+
   const selectors = (
     <div className="flex flex-wrap items-center gap-1 px-3 pt-2">
       <ExpertSelector
@@ -67,9 +74,7 @@ export function ChatContainer({
         sessionId={sessionId ?? null}
         topicId={topicId ?? null}
         settingsClosedTick={settingsClosedTick}
-        onSelectionChange={(effective) =>
+        onSelectionChange={handleModelSelectionChange}
-          setEffectiveModel({ provider: effective.provider, model: effective.model })
-        }
       />
     </div>
   );

web/src/components/Chat/MessageBubble.tsx

@@ -132,6 +132,24 @@ function formatDuration(ms: number): string {
   return `${minutes}m ${seconds}s`;
 }
 
+/**
+ * base64 → Blob 分块解码。
+ * 旧实现为 atob 全量字符串 + 装箱数字数组 + 单个巨型 Uint8Array，
+ * 50MB 附件下载瞬时占用数百 MB；分块构造后 Blob 直接接收分片，
+ * 峰值内存约为 atob 字符串 + 单个分块大小。
+ */
+function base64ToBlob(base64: string, mimeType: string): Blob {
+  const byteChars = atob(base64);
+  const total = byteChars.length;
+  const CHUNK_SIZE = 0x8000; // 32K
+  const parts: Uint8Array<ArrayBuffer>[] = [];
+  for (let offset = 0; offset < total; offset += CHUNK_SIZE) {
+    const slice = byteChars.slice(offset, offset + CHUNK_SIZE);
+    parts.push(Uint8Array.from(slice, (c) => c.charCodeAt(0)));
+  }
+  return new Blob(parts, { type: mimeType });
+}
+
 function AttachmentCard({ attachment }: { attachment: Attachment }) {
   const fileName = attachment.file_name || getFileName(attachment.path);
 
@@ -140,13 +158,7 @@ function AttachmentCard({ attachment }: { attachment: Attachment }) {
 
     e.preventDefault();
     const mimeType = attachment.mime_type || 'application/octet-stream';
-    const byteChars = atob(attachment.content_base64);
+    const blob = base64ToBlob(attachment.content_base64, mimeType);
-    const byteNums = new Array(byteChars.length);
-    for (let i = 0; i < byteChars.length; i++) {
-      byteNums[i] = byteChars.charCodeAt(i);
-    }
-    const byteArr = new Uint8Array(byteNums);
-    const blob = new Blob([byteArr], { type: mimeType });
     const url = URL.createObjectURL(blob);
 
     const a = document.createElement('a');
@@ -210,13 +222,7 @@ function ImageLightbox({
 
   const handleDownload = (e: React.MouseEvent) => {
     e.stopPropagation();
-    const byteChars = atob(src);
+    const blob = base64ToBlob(src, mimeType);
-    const byteNums = new Array(byteChars.length);
-    for (let i = 0; i < byteChars.length; i++) {
-      byteNums[i] = byteChars.charCodeAt(i);
-    }
-    const byteArr = new Uint8Array(byteNums);
-    const blob = new Blob([byteArr], { type: mimeType });
     const url = URL.createObjectURL(blob);
     const a = document.createElement('a');
     a.href = url;

web/src/components/Chat/MessageList.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useLayoutEffect, useRef, useState, useCallback } from 'react';
+import { useEffect, useLayoutEffect, useRef, useState, useCallback, useMemo } from 'react';
 import { useVirtualizer } from '@tanstack/react-virtual';
 import { MessageBubble } from './MessageBubble';
 import type { ChatMessage } from '../../types/protocol';
@@ -55,8 +55,13 @@ export function MessageList({
         : undefined,
   });
 
-  // 消息 id → virtualizer index 映射，用于 highlight 滚动定位
+  // 消息 id → virtualizer index 映射，用于 highlight 滚动定位。
-  const messageIdToIndex = useRef<Map<string, number>>(new Map());
+  // useMemo 化：仅在 messages 变化时重建，而非每次渲染（流式期间每帧一次）都全量重建。
+  const messageIdToIndex = useMemo(() => {
+    const map = new Map<string, number>();
+    messages.forEach((m, i) => map.set(m.id, i));
+    return map;
+  }, [messages]);
 
   // ---- scroll helpers ----
 
@@ -167,7 +172,7 @@ export function MessageList({
 
   useEffect(() => {
     if (!highlightedMessageId) return;
-    const idx = messageIdToIndex.current.get(highlightedMessageId);
+    const idx = messageIdToIndex.get(highlightedMessageId);
     if (idx === undefined) return;
 
     virtualizer.scrollToIndex(idx, { align: 'center', behavior: 'smooth' });
@@ -183,7 +188,7 @@ export function MessageList({
         targetElement.classList.remove('todo-highlight');
       }, 2000);
     });
-  }, [highlightedMessageId, virtualizer]);
+  }, [highlightedMessageId, messageIdToIndex, virtualizer]);
 
   // ---- 行高强制重测（修复 tanstack virtual-core 3.17.x 陈旧高度导致行重叠）----
   // 3.17.x 在滚动状态会跳过同步测量、对缓冲区外的行跳过 RO 更新并复用缓存高度；
@@ -241,10 +246,6 @@ export function MessageList({
     );
   }
 
-  // 构建消息 id → index 映射（每次渲染更新，供 highlight 查找）
-  messageIdToIndex.current.clear();
-  messages.forEach((m, i) => messageIdToIndex.current.set(m.id, i));
-
   // ---- main render ----
 
   const virtualItems = virtualizer.getVirtualItems();

web/src/hooks/chat/useSubAgentView.ts

@@ -55,6 +55,99 @@ export function useSubAgentView(options: UseSubAgentViewOptions): UseSubAgentVie
   const subAgentStackRef = useRef<SubAgentView[]>([]);
   const pendingTaskNavsRef = useRef<Map<string, string>>(new Map());
 
+  // ---- 流式 delta 批处理（镜像主视图 useMessages 的 ref 累加 + rAF flush 范式）----
+  // 每个 stream_delta 只累加到 ref，rAF 批量合并为一次 setState，
+  // 避免逐 token 触发整棵子树重渲染与双层数组拷贝。
+  interface PendingSubAgentDelta {
+    /** 'top' 表示栈顶层；否则按 taskId 定位栈中层 */
+    target: 'top' | string;
+    id: string;
+    contentChunks: string[];
+    reasoningChunks: string[];
+    /** 首个 delta 到达时创建的消息壳（含首段 content），后续 delta 追加到其后 */
+    shell: ChatMessage | null;
+  }
+  const pendingDeltasRef = useRef<Map<string, PendingSubAgentDelta>>(new Map());
+  const deltaRafRef = useRef<number | null>(null);
+  const deltaRafScheduledRef = useRef(false);
+
+  const flushSubAgentDeltas = useCallback(() => {
+    deltaRafScheduledRef.current = false;
+    const pending = pendingDeltasRef.current;
+    if (pending.size === 0) return;
+    const entries = Array.from(pending.values());
+    pending.clear();
+    setSubAgentStack((prev) => {
+      if (prev.length === 0) return prev;
+      let stack = prev;
+      for (const entry of entries) {
+        const layerIdx =
+          entry.target === 'top'
+            ? stack.length - 1
+            : stack.findIndex((v) => v.taskId === entry.target);
+        if (layerIdx < 0) continue;
+        const layer = stack[layerIdx];
+        const deltaContent = entry.contentChunks.join('');
+        const deltaReasoning =
+          entry.reasoningChunks.length > 0 ? entry.reasoningChunks.join('') : null;
+        const idx = layer.messages.findIndex((m) => m.id === entry.id && m.type === 'message');
+        const layerCopy = { ...layer };
+        if (idx >= 0) {
+          const updated = [...layer.messages];
+          const existing = updated[idx];
+          updated[idx] = {
+            ...existing,
+            content: existing.content + deltaContent,
+            reasoningContent: deltaReasoning
+              ? (existing.reasoningContent || '') + deltaReasoning
+              : existing.reasoningContent,
+          };
+          layerCopy.messages = updated;
+        } else if (entry.shell) {
+          layerCopy.messages = [
+            ...layer.messages,
+            {
+              ...entry.shell,
+              content: entry.shell.content + deltaContent,
+              reasoningContent: deltaReasoning
+                ? (entry.shell.reasoningContent || '') + deltaReasoning || undefined
+                : entry.shell.reasoningContent,
+            },
+          ];
+        } else {
+          continue;
+        }
+        const next = [...stack];
+        next[layerIdx] = layerCopy;
+        stack = next;
+      }
+      return stack;
+    });
+  }, []);
+
+  const scheduleSubAgentDeltaFlush = useCallback(() => {
+    if (deltaRafScheduledRef.current) return;
+    deltaRafScheduledRef.current = true;
+    deltaRafRef.current = requestAnimationFrame(() => flushSubAgentDeltas());
+  }, [flushSubAgentDeltas]);
+
+  /** 立即落盘待处理 delta（取消已排队的 rAF）。非 delta 消息处理前调用以保证顺序。 */
+  const flushSubAgentDeltasSync = useCallback(() => {
+    if (deltaRafRef.current !== null) {
+      cancelAnimationFrame(deltaRafRef.current);
+      deltaRafRef.current = null;
+    }
+    flushSubAgentDeltas();
+  }, [flushSubAgentDeltas]);
+
+  // 卸载时取消未执行的 flush
+  useEffect(
+    () => () => {
+      if (deltaRafRef.current !== null) cancelAnimationFrame(deltaRafRef.current);
+    },
+    [],
+  );
+
   // ref 同步：确保回调中读到最新值
   useEffect(() => {
     subAgentViewRef.current = subAgentView;
@@ -70,33 +163,24 @@ export function useSubAgentView(options: UseSubAgentViewOptions): UseSubAgentVie
     if (message.type === 'assistant_response') {
       bumpTopicRefreshTrigger();
     }
-    // stream_delta: accumulate into existing message by ID, or create new
+    // stream_delta: 累加到批处理缓冲区，rAF 统一 flush（不再逐 token setState）
     if (message.type === 'stream_delta') {
       const msg = message as StreamDelta;
-      setSubAgentStack((prev) => {
+      const pending = pendingDeltasRef.current;
-        if (prev.length === 0) return prev;
+      const entry = pending.get(msg.id);
-        const top = prev[prev.length - 1];
+      if (entry) {
-        const existingIdx = top.messages.findIndex((m) => m.id === msg.id && m.type === 'message');
+        if (msg.delta) entry.contentChunks.push(msg.delta);
-        if (existingIdx >= 0) {
+        if (msg.reasoning_delta) entry.reasoningChunks.push(msg.reasoning_delta);
-          const updated = [...top.messages];
+      } else {
-          const existing = updated[existingIdx];
+        pending.set(msg.id, {
-          updated[existingIdx] = {
+          target: 'top',
-            ...existing,
+          id: msg.id,
-            content: existing.content + msg.delta,
+          contentChunks: [],
-            reasoningContent: msg.reasoning_delta
+          reasoningChunks: [],
-              ? (existing.reasoningContent || '') + msg.reasoning_delta
+          shell: serverMessageToChatMessage(message),
-              : existing.reasoningContent,
-          };
-          const newStack = [...prev];
-          newStack[newStack.length - 1] = { ...top, messages: updated };
-          return newStack;
-        }
-        const chatMsg = serverMessageToChatMessage(message);
-        if (!chatMsg) return prev;
-        const newStack = [...prev];
-        newStack[newStack.length - 1] = { ...top, messages: [...top.messages, chatMsg] };
-        return newStack;
         });
+      }
+      scheduleSubAgentDeltaFlush();
       return;
     }
     // stream_end: no-op, assistant_response will replace
@@ -168,10 +252,31 @@ export function useSubAgentView(options: UseSubAgentViewOptions): UseSubAgentVie
         return newStack;
       });
     }
-  }, [bumpTopicRefreshTrigger]);
+  }, [bumpTopicRefreshTrigger, scheduleSubAgentDeltaFlush]);
 
   // 追加消息到栈中非栈顶的匹配层（按 taskId 匹配）
-  const appendToSubAgentLayerMessage = useCallback((taskId: string, message: WsOutbound) => {
+  const appendToSubAgentLayerMessage = useCallback(
+    (taskId: string, message: WsOutbound) => {
+      // stream_delta 在 setState 之外累加到批处理缓冲区（updater 内不允许副作用）
+      if (message.type === 'stream_delta') {
+        const msg = message as StreamDelta;
+        const pending = pendingDeltasRef.current;
+        const entry = pending.get(msg.id);
+        if (entry) {
+          if (msg.delta) entry.contentChunks.push(msg.delta);
+          if (msg.reasoning_delta) entry.reasoningChunks.push(msg.reasoning_delta);
+        } else {
+          pending.set(msg.id, {
+            target: taskId,
+            id: msg.id,
+            contentChunks: [],
+            reasoningChunks: [],
+            shell: serverMessageToChatMessage(message),
+          });
+        }
+        scheduleSubAgentDeltaFlush();
+        return;
+      }
       setSubAgentStack((prev) => {
         const idx = prev.findIndex((v) => v.taskId === taskId);
         if (idx < 0) return prev;
@@ -192,32 +297,11 @@ export function useSubAgentView(options: UseSubAgentViewOptions): UseSubAgentVie
             type: 'message',
           };
           const newStack = [...prev];
-        newStack[idx] = { ...layer, status: 'error', messages: [...layer.messages, errorChatMsg] };
+          newStack[idx] = {
-        return newStack;
+            ...layer,
-      }
+            status: 'error',
-      if (message.type === 'stream_delta') {
+            messages: [...layer.messages, errorChatMsg],
-        const msg = message as StreamDelta;
-        const existingIdx = layer.messages.findIndex(
-          (m) => m.id === msg.id && m.type === 'message',
-        );
-        if (existingIdx >= 0) {
-          const updated = [...layer.messages];
-          const existing = updated[existingIdx];
-          updated[existingIdx] = {
-            ...existing,
-            content: existing.content + msg.delta,
-            reasoningContent: msg.reasoning_delta
-              ? (existing.reasoningContent || '') + msg.reasoning_delta
-              : existing.reasoningContent,
           };
-          const newStack = [...prev];
-          newStack[idx] = { ...layer, messages: updated };
-          return newStack;
-        }
-        const chatMsg = serverMessageToChatMessage(message);
-        if (!chatMsg) return prev;
-        const newStack = [...prev];
-        newStack[idx] = { ...layer, messages: [...layer.messages, chatMsg] };
           return newStack;
         }
         if (message.type === 'stream_end') return prev;
@@ -239,14 +323,18 @@ export function useSubAgentView(options: UseSubAgentViewOptions): UseSubAgentVie
           message.type === 'tool_result' ||
           message.type === 'tool_pending'
         ) {
-        const exists = layer.messages.some((m) => m.id === chatMsg.id && m.type === chatMsg.type);
+          const exists = layer.messages.some(
+            (m) => m.id === chatMsg.id && m.type === chatMsg.type,
+          );
           if (exists) return prev;
         }
         const newStack = [...prev];
         newStack[idx] = { ...layer, messages: [...layer.messages, chatMsg] };
         return newStack;
       });
-  }, []);
+    },
+    [scheduleSubAgentDeltaFlush],
+  );
 
   const enterSubAgentView = useCallback(
     (taskId: string, description: string, subagentType?: string): Command => {
@@ -267,6 +355,8 @@ export function useSubAgentView(options: UseSubAgentViewOptions): UseSubAgentVie
   );
 
   const exitSubAgentView = useCallback((): Command | null => {
+    // 栈变更前先落盘待处理 delta，避免丢失或写入清空后的新栈
+    flushSubAgentDeltasSync();
     const current = subAgentStackRef.current;
     if (current.length <= 1) {
       subAgentViewRef.current = null;
@@ -282,9 +372,12 @@ export function useSubAgentView(options: UseSubAgentViewOptions): UseSubAgentVie
     subAgentStackRef.current = clearedStack;
     setSubAgentStack(clearedStack);
     return { type: 'load_task_messages', task_id: newTop.taskId };
-  }, []);
+  }, [flushSubAgentDeltasSync]);
 
-  const navigateToSubAgentLevel = useCallback((index: number): Command | null => {
+  const navigateToSubAgentLevel = useCallback(
+    (index: number): Command | null => {
+      // 栈变更前先落盘待处理 delta，避免丢失或写入清空后的新栈
+      flushSubAgentDeltasSync();
       const current = subAgentStackRef.current;
       if (index < 0) {
         subAgentViewRef.current = null;
@@ -301,7 +394,9 @@ export function useSubAgentView(options: UseSubAgentViewOptions): UseSubAgentVie
       subAgentStackRef.current = clearedStack;
       setSubAgentStack(clearedStack);
       return { type: 'load_task_messages', task_id: newTop.taskId };
-  }, []);
+    },
+    [flushSubAgentDeltasSync],
+  );
 
   /** Tier 2 路由：子智能体视图激活时处理消息，返回是否已处理 */
   const handleSubAgentMessage = useCallback(
@@ -309,6 +404,11 @@ export function useSubAgentView(options: UseSubAgentViewOptions): UseSubAgentVie
       const currentSubAgentView = subAgentViewRef.current;
       if (!currentSubAgentView) return false;
 
+      // 非 delta 消息处理前先落盘待处理的 delta，保证消息顺序与内容完整性
+      if (message.type !== 'stream_delta' && pendingDeltasRef.current.size > 0) {
+        flushSubAgentDeltasSync();
+      }
+
       if (message.type === 'task_messages_loaded') {
         const msg = message as TaskMessagesLoaded;
         setSubAgentStack((prev) => {
@@ -431,6 +531,7 @@ export function useSubAgentView(options: UseSubAgentViewOptions): UseSubAgentVie
       appendToSubAgentLayerMessage,
       sendCommand,
       requestSubAgentTodoList,
+      flushSubAgentDeltasSync,
     ],
   );