refactor(data): add I*Repository interfaces and depend on them in stores

为 /src/data/repositories/ 下每个仓库类增加对应的接口契约，
接口文件存放在独立的 interfaces/ 子目录中。

改动:
- 新建 4 个接口文件 (iauth_repository / ichat_repository /
  imetrics_repository / iuser_repository)，纯 type-only，方法签名
  与实现类完全一致
- 4 个实现类加 implements I{Name}Repository 子句，编译器自动校验契约
- 3 个 stores 文件 (auth / chat / user state machines) 改为依赖接口
  类型：通过 `const xxxRepo: I{Name}Repository = xxxRepository` 局部别名，
  actor 内部调用全部走别名
- barrelsby.json 加入 interfaces/ 目录，让自动 barrel 能覆盖
- Auto-regenerated repositories/index.ts 与 interfaces/index.ts

参照 storage 层已有的 IAuthStorage / IChatStorage / IUserStorage 模式。

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/stores/chat/chat-machine.ts

@@ -18,6 +18,7 @@ import { setup, fromPromise, assign } from "xstate";
 
 import type { UiMessage } from "@/models/chat/ui-message";
 import { chatRepository } from "@/data/repositories/chat_repository";
+import type { IChatRepository } from "@/data/repositories/interfaces";
 import { ChatStorage } from "@/data/storage/chat/chat_storage";
 import { AuthStorage } from "@/data/storage/auth/auth_storage";
 import { formatDate } from "@/utils/date";
@@ -72,6 +73,9 @@ function mapTotalQuotaResult(
   return fallback;
 }
 
+// 仓库以接口类型注入：调用面只看接口，运行时仍是同一单例
+const chatRepo: IChatRepository = chatRepository;
+
 interface InitResult {
   localMessages: UiMessage[];
   isGuest: boolean;
@@ -86,7 +90,7 @@ async function readInitData(): Promise<InitResult> {
   const [dailyResult, totalResult, localResult] = await Promise.all([
     chatStorage.getGuestDailyChatQuota(),
     chatStorage.getGuestTotalQuota(),
-    isGuest ? chatRepository.getLocalMessages() : Promise.resolve(null),
+    isGuest ? chatRepo.getLocalMessages() : Promise.resolve(null),
   ]);
 
   return {
@@ -115,11 +119,11 @@ const sendMessageHttpActor = fromPromise<
   { messages: UiMessage[] },
   { content: string }
 >(async ({ input }) => {
-  const result = await chatRepository.sendMessage(input.content);
+  const result = await chatRepo.sendMessage(input.content);
   if (Result.isErr(result)) throw result.error;
 
   // 拉取最新本地历史
-  const local = await chatRepository.getLocalMessages();
+  const local = await chatRepo.getLocalMessages();
   if (Result.isOk(local) && local.data) {
     return { messages: localMessagesToUi(local.data) };
   }
@@ -130,7 +134,7 @@ const loadMoreHistoryActor = fromPromise<
   { messages: UiMessage[]; hasMore: boolean; newOffset: number },
   { offset: number }
 >(async ({ input }) => {
-  const result = await chatRepository.getHistory(PAGE_SIZE, input.offset);
+  const result = await chatRepo.getHistory(PAGE_SIZE, input.offset);
   if (Result.isErr(result)) throw result.error;
 
   const page = localMessagesToUi(result.data.messages);