feat: 多功能升级 — 流式逐字渲染、对话缓存、会话组织优化、记忆管理修复、性能仪表盘

- 前端消息流式逐字渲染 (AI-Core ChatStream → SSE → Gateway → WebSocket stream_chunk → fadeInUp + cursorBlink)
- 后端对话缓存 (conversationCache sync.Map, GET /sessions/:id/messages)
- 前端侧边栏历史多轮对话显示
- DevTools 性能监控图标移至首页仪表盘
- DevTools 用户记忆查询/删减功能修复 (补全 DELETE 数据链路)
- 后端和 DevTools 按用户分类组织实时活动会话 (map[userID]map[sessionID]*Client)
- 新增 docs/api-reference/ 路由参考文档
- 新增 docs/message-flow-architecture.md 消息链路架构文档

frontend/web/src/store/chatStore.ts

@@ -6,6 +6,8 @@ interface ChatStore {
   isTyping: boolean;
 
   addMessage: (message: Message) => void;
+  appendToLastMessage: (content: string) => void;
+  finishStreaming: () => void;
   setMessages: (messages: Message[]) => void;
   setTyping: (typing: boolean) => void;
   clearMessages: () => void;
@@ -17,9 +19,41 @@ export const useChatStore = create<ChatStore>((set) => ({
 
   addMessage: (message) =>
     set((state) => ({
-      messages: [...state.messages, message],
+      messages: [
+        ...state.messages,
+        {
+          ...message,
+          isStreaming: message.role === 'assistant' ? (message.isStreaming ?? true) : message.isStreaming,
+        },
+      ],
     })),
 
+  appendToLastMessage: (content) =>
+    set((state) => {
+      const msgs = [...state.messages];
+      const last = msgs[msgs.length - 1];
+      if (last && last.role === 'assistant' && last.isStreaming) {
+        msgs[msgs.length - 1] = {
+          ...last,
+          content: last.content + content,
+        };
+      }
+      return { messages: msgs };
+    }),
+
+  finishStreaming: () =>
+    set((state) => {
+      const msgs = [...state.messages];
+      const last = msgs[msgs.length - 1];
+      if (last && last.role === 'assistant' && last.isStreaming) {
+        msgs[msgs.length - 1] = {
+          ...last,
+          isStreaming: false,
+        };
+      }
+      return { messages: msgs, isTyping: false };
+    }),
+
   setMessages: (messages) => set({ messages }),
 
   setTyping: (typing) => set({ isTyping: typing }),

frontend/web/src/store/sessionStore.ts

@@ -1,22 +1,29 @@
 import { create } from 'zustand';
 import type { Session } from '@/types/session';
+import type { Message } from '@/types/chat';
+import { fetchSessionMessages as apiFetchMessages } from '@/api/client';
+import { useChatStore } from '@/store/chatStore';
 
 interface SessionStore {
   sessions: Session[];
   currentSessionId: string | null;
   loading: boolean;
+  messages: Message[];
 
   setSessions: (sessions: Session[]) => void;
   addSession: (session: Session) => void;
   removeSession: (id: string) => void;
   setCurrentSessionId: (id: string | null) => void;
   setLoading: (loading: boolean) => void;
+  setMessages: (messages: Message[]) => void;
+  clearMessages: () => void;
 }
 
 export const useSessionStore = create<SessionStore>((set) => ({
   sessions: [],
   currentSessionId: null,
   loading: false,
+  messages: [],
 
   setSessions: (sessions) => set({ sessions }),
   addSession: (session) =>
@@ -25,7 +32,44 @@ export const useSessionStore = create<SessionStore>((set) => ({
     set((state) => ({
       sessions: state.sessions.filter((s) => s.id !== id),
       currentSessionId: state.currentSessionId === id ? null : state.currentSessionId,
+      messages: state.currentSessionId === id ? [] : state.messages,
     })),
-  setCurrentSessionId: (id) => set({ currentSessionId: id }),
+  setCurrentSessionId: async (id) => {
+    set({ currentSessionId: id, loading: true });
+
+    // 清除旧消息（同时清 chatStore）
+    if (id === null) {
+      set({ messages: [], loading: false });
+      useChatStore.getState().clearMessages();
+      return;
+    }
+
+    // 从后端加载历史消息
+    try {
+      const resp = await apiFetchMessages(id);
+      if (resp.data) {
+        const data = resp.data as { messages: Message[] };
+        const msgs = data.messages || [];
+        set({ messages: msgs, loading: false });
+        // 同步到 chatStore 以便 ChatContainer 渲染
+        useChatStore.getState().setMessages(msgs);
+      } else {
+        set({ messages: [], loading: false });
+        useChatStore.getState().clearMessages();
+      }
+    } catch {
+      set({ messages: [], loading: false });
+      useChatStore.getState().clearMessages();
+    }
+  },
   setLoading: (loading) => set({ loading }),
+  setMessages: (messages) => {
+    set({ messages });
+    // 同步到 chatStore
+    useChatStore.getState().setMessages(messages);
+  },
+  clearMessages: () => {
+    set({ messages: [] });
+    useChatStore.getState().clearMessages();
+  },
 }));