refactor(env, i18n, http): 更新环境配置与错误提示信息

修改 .env.example，简化 API 配置说明并明确生产环境要求。更新多语言错误提示，确保用户在未启用 API 代理时获得清晰反馈。重构 admin-http.ts，优化 API 基础 URL 的解析逻辑，提升代码可维护性。

src/lib/admin-http.ts

@@ -8,12 +8,12 @@ import { withAdminAuthHeader } from "@/lib/admin-auth";
 import { withAdminLocaleHeaders } from "@/lib/admin-locale";
 import { LotteryApiBizError, LotteryApiEnvelopeError } from "@/types/api/errors";
 import { isApiEnvelope } from "@/types/api/envelope";
-import { LOTTERY_API_V1_BASE } from "@/api/paths";
+import { resolveLotteryApiV1Base } from "@/lib/lottery-api-base";
 
 export { hasLotteryAdminApiBaseUrl } from "@/lib/lottery-api-env";
 
 export const adminHttp = axios.create({
-  baseURL: LOTTERY_API_V1_BASE,
+  baseURL: resolveLotteryApiV1Base(),
   timeout: 30_000,
   headers: { Accept: "application/json" },
 });