feat: trial 赠送改为白名单邮箱域名控制

- 新增 EnableTrialEmailWhitelist + TrialEmailDomainWhitelist 配置
- 邮箱注册/登录：加白名单域名判断，域名匹配才赠送 trial
- 设备登录/手机注册：移除 activeTrial，不再自动赠送
- 绑定邮箱(bindEmailWithVerification)：绑定成功后检查白名单+防重复赠送
- 新增 IsEmailDomainWhitelisted 导出函数供跨包调用
- 清理 deviceLoginLogic/telephoneUserRegisterLogic 中的 activeTrial 死代码

Co-Authored-By: claude-flow <ruv@ruv.net>

internal/logic/auth/trialEmailWhitelist.go

@@ -0,0 +1,22 @@
+package auth
+
+import "strings"
+
+// IsEmailDomainWhitelisted checks if the email's domain is in the comma-separated whitelist.
+// Returns false if the email format is invalid.
+func IsEmailDomainWhitelisted(email, whitelistCSV string) bool {
+	if whitelistCSV == "" {
+		return false
+	}
+	parts := strings.SplitN(email, "@", 2)
+	if len(parts) != 2 {
+		return false
+	}
+	domain := strings.ToLower(strings.TrimSpace(parts[1]))
+	for _, d := range strings.Split(whitelistCSV, ",") {
+		if strings.ToLower(strings.TrimSpace(d)) == domain {
+			return true
+		}
+	}
+	return false
+}