feat(dcauth): 移除机器码，改用纯设备码认证

- DCAuth 协议升级到 v2，签名原文只含设备码；客户端 2.0.0，旧版本返回 426
- 删除客户端机器码采集、后端 machine_code_* 字段与日志、后台机器码展示
- 102 迁移在生产执行前直接改为无机器码结构；SQL 守卫仅放行该文件
- Mock 短信不启用每日限额；修复慢电脑首次启动的协议转发竞态
- 新增 macOS DCAuth.app 打包脚本，注册 dcauth:// 协议，浏览器可直接唤起

apps/backend/src/services/admin/admin-sms-service.ts

@@ -67,6 +67,9 @@ export async function sendAdminLoginSmsCode(
   }
 
   const config = runtimeConfig.worker.sms
+  const provider = String(config.provider || 'mock')
+    .trim()
+    .toLowerCase()
   const cooldownMs = Math.max(10, Number(config.cooldownSeconds || 60)) * 1000
   const dailyLimit = Math.max(1, Number(config.dailyLimit || 10))
   const ttlSeconds = Math.max(60, Number(config.codeTtlSeconds || 300))
@@ -84,6 +87,7 @@ export async function sendAdminLoginSmsCode(
 
   const dayRange = resolveChinaDayRange()
   if (
+    shouldEnforceAdminSmsDailyLimit(provider) &&
     (await countAdminSmsCodesOnDay(Number(user.id), dayRange.start, dayRange.end)) >= dailyLimit
   ) {
     throw createHttpError('今日验证码发送次数已达上限，请明天再试', {
@@ -185,6 +189,14 @@ function generateSmsCode(): string {
   return code
 }
 
+export function shouldEnforceAdminSmsDailyLimit(providerValue: unknown): boolean {
+  return (
+    String(providerValue || 'mock')
+      .trim()
+      .toLowerCase() !== 'mock'
+  )
+}
+
 function normalizeAdminUsername(value: unknown): string {
   return String(value || '')
     .trim()