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/dcauth/base32.go

@@ -2,8 +2,6 @@ package main
 
 import (
 	"crypto/sha256"
-	"fmt"
-	"sort"
 	"strings"
 )
 
@@ -15,25 +13,6 @@ func buildDeviceID(publicKey []byte) string {
 	return formatCode("D1", sum[:])
 }
 
-func buildMachineCode() (string, error) {
-	components, err := collectHardwareComponents()
-	if err != nil {
-		return "", err
-	}
-	keys := make([]string, 0, len(components))
-	for key := range components {
-		keys = append(keys, key)
-	}
-	sort.Strings(keys)
-
-	parts := []string{"dcauth.machine.v1"}
-	for _, key := range keys {
-		parts = append(parts, key+"="+components[key])
-	}
-	sum := sha256.Sum256([]byte(strings.Join(parts, "\n")))
-	return formatCode("M1", sum[:]), nil
-}
-
 func formatCode(prefix string, data []byte) string {
 	encoded := base32Crockford(data)
 	if len(encoded) > 20 {
@@ -68,22 +47,3 @@ func base32Crockford(data []byte) string {
 	}
 	return builder.String()
 }
-
-func normalizeComponent(value string) string {
-	normalized := strings.ToUpper(strings.TrimSpace(value))
-	normalized = strings.Join(strings.Fields(normalized), "")
-	switch normalized {
-	case "", "0", "NONE", "N/A", "NA", "UNKNOWN", "DEFAULTSTRING",
-		"TOBEFILLEDBYO.E.M.", "TOBEFILLEDBYOEM", "SYSTEMSERIALNUMBER",
-		"00000000-0000-0000-0000-000000000000":
-		return ""
-	}
-	return normalized
-}
-
-func ensureNotEmpty(components map[string]string) error {
-	if len(components) == 0 {
-		return fmt.Errorf("无法读取本机硬件信息，请联系管理员")
-	}
-	return nil
-}