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/volcengine_acme.go

@@ -0,0 +1,89 @@
+package ddns
+
+import (
+	"context"
+	"strings"
+
+	"github.com/volcengine/volcengine-go-sdk/service/dns"
+	"github.com/volcengine/volcengine-go-sdk/volcengine"
+)
+
+// UpsertTXTRecord creates or updates a TXT record for ACME DNS-01.
+func (v *Volcengine) UpsertTXTRecord(ctx context.Context, cred Credentials, fqdn, value string) error {
+	zone, host, err := ResolveZoneForFQDN(ctx, func(candidate string) (bool, error) {
+		return v.HasZone(ctx, cred, candidate)
+	}, fqdn)
+	if err != nil {
+		return err
+	}
+	return v.UpdateRecord(ctx, cred, zone, host, "TXT", value)
+}
+
+// DeleteTXTRecord removes TXT records matching value at fqdn (ACME cleanup).
+func (v *Volcengine) DeleteTXTRecord(ctx context.Context, cred Credentials, fqdn, value string) error {
+	zone, host, err := ResolveZoneForFQDN(ctx, func(candidate string) (bool, error) {
+		return v.HasZone(ctx, cred, candidate)
+	}, fqdn)
+	if err != nil {
+		return err
+	}
+	return v.deleteTXTRecords(ctx, cred, zone, host, value)
+}
+
+func (v *Volcengine) deleteTXTRecords(ctx context.Context, cred Credentials, rootDomain, recordName, value string) error {
+	client, err := v.client(cred)
+	if err != nil {
+		return err
+	}
+	zid, err := v.zoneID(ctx, client, rootDomain)
+	if err != nil {
+		return err
+	}
+	host := volcengineHost(recordName)
+	records, err := v.listRecords(ctx, client, zid, host, "TXT")
+	if err != nil {
+		return err
+	}
+	for _, rec := range records {
+		if rec.Value == nil || strings.TrimSpace(*rec.Value) != strings.TrimSpace(value) {
+			continue
+		}
+		if rec.RecordID == nil {
+			continue
+		}
+		if _, err := client.DeleteRecordWithContext(ctx, &dns.DeleteRecordInput{
+			RecordID: rec.RecordID,
+		}); err != nil {
+			return wrapVolcengineErr(err)
+		}
+	}
+	return nil
+}
+
+func (v *Volcengine) listRecords(ctx context.Context, client *dns.DNS, zid int64, host, recordType string) ([]*dns.RecordForListRecordsOutput, error) {
+	var out []*dns.RecordForListRecordsOutput
+	var page int32 = 1
+	const pageSize int32 = 100
+	for {
+		resp, err := client.ListRecordsWithContext(ctx, &dns.ListRecordsInput{
+			ZID:        volcengine.Int64(zid),
+			Host:       volcengine.String(host),
+			Type:       volcengine.String(recordType),
+			PageNumber: volcengine.Int32(page),
+			PageSize:   volcengine.Int32(pageSize),
+		})
+		if err != nil {
+			return nil, wrapVolcengineErr(err)
+		}
+		out = append(out, resp.Records...)
+		total := int32(0)
+		if resp.TotalCount != nil {
+			total = *resp.TotalCount
+		}
+		if len(resp.Records) == 0 || page*pageSize >= total {
+			break
+		}
+		page++
+	}
+	return out, nil
+}