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/api/backup_handler.go

@@ -0,0 +1,73 @@
+package api
+
+import (
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+
+	"github.com/fonu/fonu/internal/backup"
+)
+
+type BackupHandler struct {
+	svc *backup.Service
+}
+
+func NewBackupHandler(svc *backup.Service) *BackupHandler {
+	return &BackupHandler{svc: svc}
+}
+
+func (h *BackupHandler) Export(w http.ResponseWriter, r *http.Request) {
+	path, err := h.svc.Export(r.Context())
+	if err != nil {
+		writeError(r, w, http.StatusInternalServerError, "创建备份失败")
+		return
+	}
+	defer os.Remove(path)
+
+	file, err := os.Open(path)
+	if err != nil {
+		writeError(r, w, http.StatusInternalServerError, "读取备份失败")
+		return
+	}
+	defer file.Close()
+
+	w.Header().Set("Content-Type", "application/gzip")
+	w.Header().Set("Content-Disposition", "attachment; filename="+filepath.Base(path))
+	_, _ = io.Copy(w, file)
+}
+
+func (h *BackupHandler) Restore(w http.ResponseWriter, r *http.Request) {
+	if err := r.ParseMultipartForm(64 << 20); err != nil {
+		writeError(r, w, http.StatusBadRequest, "上传文件无效")
+		return
+	}
+	file, header, err := r.FormFile("file")
+	if err != nil {
+		writeError(r, w, http.StatusBadRequest, "请选择备份文件")
+		return
+	}
+	defer file.Close()
+
+	tmpPath := filepath.Join(os.TempDir(), header.Filename)
+	out, err := os.Create(tmpPath)
+	if err != nil {
+		writeError(r, w, http.StatusInternalServerError, "保存上传文件失败")
+		return
+	}
+	if _, err := io.Copy(out, file); err != nil {
+		out.Close()
+		_ = os.Remove(tmpPath)
+		writeError(r, w, http.StatusInternalServerError, "保存上传文件失败")
+		return
+	}
+	out.Close()
+
+	if err := h.svc.Restore(r.Context(), tmpPath); err != nil {
+		_ = os.Remove(tmpPath)
+		writeError(r, w, http.StatusBadRequest, err.Error())
+		return
+	}
+	_ = os.Remove(tmpPath)
+	writeJSON(w, http.StatusOK, map[string]string{"message": "备份已恢复，建议重启 Fonu"})
+}