chore: 初始提交 Fonu 1.0.2

- 公网反代：Nginx 状态卡片（版本 / 运行状态 / 配置校验 / 端口监听）
- 部署设置第一、二梯队（HTTPS 开关、安全头、限流、连接数、仅中国大陆 IP）
- 隧道检测兼容 frps v0.68 / v0.71（V2 与旧版端点）
- 恢复被清空的 internal/frp/store.go、internal/api/ddns_handler.go、web/src/views/DdnsView.vue

internal/ddns/zone.go

@@ -0,0 +1,87 @@
+package ddns
+
+import (
+	"context"
+	"fmt"
+	"strings"
+)
+
+type zoneChecker func(zone string) (bool, error)
+
+// ResolveZoneForFQDN finds the longest DNS zone suffix that exists at the provider.
+// For delegated zones (e.g. sub.example.com hosted separately), it prefers sub.example.com over example.com.
+func ResolveZoneForFQDN(ctx context.Context, check zoneChecker, fqdn string) (zone, host string, err error) {
+	fqdn = strings.ToLower(strings.TrimSpace(strings.TrimSuffix(fqdn, ".")))
+	if fqdn == "" {
+		return "", "", fmt.Errorf("域名不能为空")
+	}
+
+	if strings.HasPrefix(fqdn, "*.") {
+		zone, host, err := ResolveZoneForFQDN(ctx, check, strings.TrimPrefix(fqdn, "*."))
+		if err != nil {
+			return "", "", err
+		}
+		if host == "@" {
+			return zone, "*", nil
+		}
+		return zone, "*." + host, nil
+	}
+
+	parts := strings.Split(fqdn, ".")
+	if len(parts) < 2 {
+		return "", "", fmt.Errorf("域名格式无效: %s", fqdn)
+	}
+
+	for i := 0; i < len(parts)-1; i++ {
+		candidate := strings.Join(parts[i:], ".")
+		ok, err := check(candidate)
+		if err != nil {
+			return "", "", err
+		}
+		if !ok {
+			continue
+		}
+		host := "@"
+		if i > 0 {
+			host = strings.Join(parts[:i], ".")
+		}
+		return candidate, host, nil
+	}
+	return "", "", fmt.Errorf("未在 DNS 服务商中找到域名 %s 对应的 Zone", fqdn)
+}
+
+func FQDNFromRecord(cfg Config, name string) string {
+	name = strings.TrimSpace(strings.ToLower(name))
+	if name == "" {
+		return strings.ToLower(strings.TrimSpace(cfg.RootDomain))
+	}
+	if strings.Contains(name, ".") || strings.HasPrefix(name, "*.") {
+		root, record, err := parseDomainLine(name)
+		if err == nil {
+			return FormatDomainLine(root, record)
+		}
+		return strings.TrimSuffix(name, ".")
+	}
+	return FormatDomainLine(cfg.RootDomain, name)
+}
+
+func isZoneNotFound(err error) bool {
+	if err == nil {
+		return false
+	}
+	msg := strings.ToLower(err.Error())
+	return strings.Contains(msg, "未找到") ||
+		strings.Contains(msg, "not found") ||
+		strings.Contains(msg, "resourcenotfound") ||
+		strings.Contains(msg, "invaliddomain")
+}
+
+func zoneLookupOK(err error) (bool, error) {
+	if err == nil {
+		return true, nil
+	}
+	if isZoneNotFound(err) {
+		return false, nil
+	}
+	return false, err
+}