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/acme/download.go

@@ -0,0 +1,117 @@
+package acme
+
+import (
+	"archive/zip"
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	certstore "github.com/fonu/fonu/internal/certificate"
+)
+
+type DownloadPart string
+
+const (
+	DownloadZIP  DownloadPart = "zip"
+	DownloadCert DownloadPart = "cert"
+	DownloadKey  DownloadPart = "key"
+)
+
+func (s *Service) Download(ctx context.Context, domain string, part string) (filename string, contentType string, data []byte, err error) {
+	domain = strings.ToLower(strings.TrimSpace(domain))
+	if domain == "" {
+		return "", "", nil, fmt.Errorf("域名不能为空")
+	}
+
+	rec, err := s.store.GetByDomain(ctx, domain)
+	if err != nil {
+		return "", "", nil, err
+	}
+	if rec.CertPath == "" || rec.KeyPath == "" {
+		return "", "", nil, fmt.Errorf("证书文件不存在，可能尚未申请成功")
+	}
+	if err := validateCertFilePath(s.cfg.CertsDir(), rec.CertPath); err != nil {
+		return "", "", nil, err
+	}
+	if err := validateCertFilePath(s.cfg.CertsDir(), rec.KeyPath); err != nil {
+		return "", "", nil, err
+	}
+
+	certPEM, err := os.ReadFile(rec.CertPath)
+	if err != nil {
+		return "", "", nil, fmt.Errorf("读取证书失败")
+	}
+	keyPEM, err := os.ReadFile(rec.KeyPath)
+	if err != nil {
+		return "", "", nil, fmt.Errorf("读取私钥失败")
+	}
+
+	base := downloadBaseName(rec)
+	switch DownloadPart(strings.ToLower(strings.TrimSpace(part))) {
+	case "", DownloadZIP:
+		data, err = zipCertBundle(base, certPEM, keyPEM)
+		if err != nil {
+			return "", "", nil, err
+		}
+		return base + ".zip", "application/zip", data, nil
+	case DownloadCert:
+		return base + "-fullchain.pem", "application/x-pem-file", certPEM, nil
+	case DownloadKey:
+		return base + "-privatekey.pem", "application/x-pem-file", keyPEM, nil
+	default:
+		return "", "", nil, fmt.Errorf("不支持的下载类型")
+	}
+}
+
+func downloadBaseName(rec certstore.Record) string {
+	name := strings.TrimPrefix(rec.Domain, "*.")
+	name = strings.ReplaceAll(name, "*", "wildcard")
+	name = strings.ReplaceAll(name, "/", "_")
+	if name == "" {
+		name = "certificate"
+	}
+	return name
+}
+
+func validateCertFilePath(certsDir, path string) error {
+	absCerts, err := filepath.Abs(certsDir)
+	if err != nil {
+		return fmt.Errorf("证书目录无效")
+	}
+	absPath, err := filepath.Abs(path)
+	if err != nil {
+		return fmt.Errorf("证书路径无效")
+	}
+	rel, err := filepath.Rel(absCerts, absPath)
+	if err != nil || strings.HasPrefix(rel, "..") {
+		return fmt.Errorf("证书路径无效")
+	}
+	return nil
+}
+
+func zipCertBundle(base string, certPEM, keyPEM []byte) ([]byte, error) {
+	var buf bytes.Buffer
+	zw := zip.NewWriter(&buf)
+	if err := writeZipEntry(zw, "fullchain.pem", certPEM); err != nil {
+		return nil, err
+	}
+	if err := writeZipEntry(zw, "privatekey.pem", keyPEM); err != nil {
+		return nil, err
+	}
+	if err := zw.Close(); err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
+func writeZipEntry(zw *zip.Writer, name string, data []byte) error {
+	w, err := zw.Create(name)
+	if err != nil {
+		return err
+	}
+	_, err = w.Write(data)
+	return err
+}