refactor: migrate state imports from contexts to stores directory

src/stores/chat/chat-context.tsx

@@ -0,0 +1,85 @@
+"use client";
+/**
+ * ChatContext：基于 XState v5 的 React Context Provider
+ *
+ * 业务事件通过 `useMachine(chatMachine).send()` 派发。
+ * XState 自动处理 HTTP 副作用（invoke + fromPromise actors）。
+ *
+ * 兼容性：保持原 `useChatState()` / `useChatDispatch()` API。
+ * 内部将 XState 状态机快照映射回原 `ChatState` 形状。
+ *
+ * 注：WebSocket 长生命周期 actor 暂未集成到状态机（保留在 chat-side-effects.ts
+ * 由外部 chat-side-effects 模块管理），待下一轮迁移。
+ */
+import {
+  type Dispatch,
+  type ReactNode,
+  createContext,
+  useContext,
+  useMemo,
+} from "react";
+import { useMachine } from "@xstate/react";
+
+import { chatMachine } from "./chat-machine";
+import type { ChatEvent, ChatContext as MachineContext } from "./chat-machine";
+
+/**
+ * 对外暴露的 State 形状（保持与原 ChatState 兼容）
+ */
+export interface ChatState {
+  messages: MachineContext["messages"];
+  isReplyingAI: boolean;
+  isGuest: boolean;
+  guestRemainingQuota: number;
+  guestTotalQuota: number;
+  quotaExceededTrigger: number;
+  isLoadingMore: boolean;
+  hasMore: boolean;
+  historyOffset: number;
+}
+
+const ChatStateCtx = createContext<ChatState | null>(null);
+const ChatDispatchCtx = createContext<Dispatch<ChatEvent> | null>(null);
+
+export interface ChatProviderProps {
+  children: ReactNode;
+}
+
+export function ChatProvider({ children }: ChatProviderProps) {
+  const [state, send] = useMachine(chatMachine);
+
+  // 映射 XState 状态机快照 → 原 ChatState 形状
+  const chatState = useMemo<ChatState>(
+    () => ({
+      messages: state.context.messages,
+      isReplyingAI: state.context.isReplyingAI,
+      isGuest: state.context.isGuest,
+      guestRemainingQuota: state.context.guestRemainingQuota,
+      guestTotalQuota: state.context.guestTotalQuota,
+      quotaExceededTrigger: state.context.quotaExceededTrigger,
+      isLoadingMore: state.context.isLoadingMore,
+      hasMore: state.context.hasMore,
+      historyOffset: state.context.historyOffset,
+    }),
+    [state],
+  );
+
+  return (
+    <ChatStateCtx.Provider value={chatState}>
+      <ChatDispatchCtx.Provider value={send}>{children}</ChatDispatchCtx.Provider>
+    </ChatStateCtx.Provider>
+  );
+}
+
+export function useChatState(): ChatState {
+  const ctx = useContext(ChatStateCtx);
+  if (!ctx) throw new Error("useChatState must be used inside <ChatProvider>");
+  return ctx;
+}
+
+export function useChatDispatch(): Dispatch<ChatEvent> {
+  const ctx = useContext(ChatDispatchCtx);
+  if (!ctx)
+    throw new Error("useChatDispatch must be used inside <ChatProvider>");
+  return ctx;
+}