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/frp/location.go

@@ -0,0 +1,99 @@
+package frp
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"net"
+	"net/http"
+	"strings"
+	"time"
+)
+
+const locationCacheTTL = 24 * time.Hour
+
+type locationCache struct {
+	value     string
+	expiresAt time.Time
+}
+
+type ipLocationResponse struct {
+	Success bool   `json:"success"`
+	City    string `json:"city"`
+	Region  string `json:"region"`
+	Country string `json:"country"`
+}
+
+func (s *Service) serverLocation(ctx context.Context, host string) string {
+	ip := resolvePublicIP(ctx, host)
+	if ip == "" {
+		return strings.TrimSpace(host)
+	}
+	s.locationMu.Lock()
+	if cached, ok := s.locations[ip]; ok && time.Now().Before(cached.expiresAt) {
+		s.locationMu.Unlock()
+		return cached.value
+	}
+	s.locationMu.Unlock()
+	value := lookupIPLocation(ctx, ip)
+	// 定位失败只是展示信息缺失：缓存 IP 本身,不产生错误状态,下一次诊断会再次尝试
+	s.locationMu.Lock()
+	s.locations[ip] = locationCache{value: value, expiresAt: time.Now().Add(locationCacheTTL)}
+	s.locationMu.Unlock()
+	return value
+}
+
+func resolvePublicIP(ctx context.Context, host string) string {
+	if ip := net.ParseIP(host); isPublicIP(ip) {
+		return ip.String()
+	}
+	addresses, err := net.DefaultResolver.LookupIPAddr(ctx, host)
+	if err != nil {
+		return ""
+	}
+	for _, address := range addresses {
+		if isPublicIP(address.IP) {
+			return address.IP.String()
+		}
+	}
+	return ""
+}
+
+func isPublicIP(ip net.IP) bool {
+	return ip != nil && ip.IsGlobalUnicast() && !ip.IsPrivate() && !ip.IsLoopback() && !ip.IsLinkLocalUnicast()
+}
+
+func lookupIPLocation(ctx context.Context, ip string) string {
+	request, err := http.NewRequestWithContext(ctx, http.MethodGet, "https://ipwho.is/"+ip, nil)
+	if err != nil {
+		return "未定位"
+	}
+	client := &http.Client{Timeout: 4 * time.Second}
+	response, err := client.Do(request)
+	if err != nil {
+		return "未定位"
+	}
+	defer response.Body.Close()
+	if response.StatusCode != http.StatusOK {
+		return "未定位"
+	}
+	var data ipLocationResponse
+	if err := json.NewDecoder(io.LimitReader(response.Body, 128<<10)).Decode(&data); err != nil || !data.Success {
+		return "未定位"
+	}
+	return formatLocation(data)
+}
+
+func formatLocation(data ipLocationResponse) string {
+	parts := []string{data.City, data.Region, data.Country}
+	values := make([]string, 0, len(parts))
+	for _, part := range parts {
+		if part != "" && (len(values) == 0 || values[len(values)-1] != part) {
+			values = append(values, part)
+		}
+	}
+	if len(values) == 0 {
+		return "未定位"
+	}
+	return strings.Join(values, " · ")
+}