Add Radar DC Telegram functionality and configuration

- Introduced new `RadarConfig` structure in `config.go` to manage radar settings, including `statuses_url`, `http_timeout_ms`, and `ping_from`.
- Implemented validation for radar configuration in `config_test.go` to ensure correct URL schemes and timeout limits.
- Added new API routes for radar statuses and ping functionality in the gateway, enhancing the service's capabilities.
- Updated documentation in `GATEWAY_RUN.md` to include details about the new radar features and their usage.
- Enhanced the user interface to include navigation and display options for the Radar DC section in the sidebar and page titles.
- Added client-side API functions for fetching radar statuses and ping responses, improving integration with the frontend.

internal/server/radar.go

@@ -0,0 +1,124 @@
+package server
+
+import (
+	"encoding/json"
+	"io"
+	"net"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const defaultRadarStatusesURL = "https://radar.telemt.top/api/v1/endpoints/statuses"
+
+// telegramDC443 — IPv4 DC Telegram для MTProto (как в ping_proxy.php исходной панели).
+var telegramDC443 = map[int]string{
+	1: "149.154.175.50",
+	2: "149.154.167.51",
+	3: "149.154.175.100",
+	4: "149.154.167.91",
+	5: "149.154.171.5",
+}
+
+func (g *Gateway) serveRadar(w http.ResponseWriter, r *http.Request) {
+	switch r.URL.Path {
+	case "/api/radar/statuses":
+		if r.Method != http.MethodGet {
+			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+			return
+		}
+		g.serveRadarStatuses(w, r)
+	case "/api/radar/ping-dc":
+		if r.Method != http.MethodGet {
+			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+			return
+		}
+		g.serveRadarPingDC(w, r)
+	default:
+		http.NotFound(w, r)
+	}
+}
+
+// serveRadarStatuses проксирует JSON radar.telemt.top (аналог radar_proxy.php).
+func (g *Gateway) serveRadarStatuses(w http.ResponseWriter, r *http.Request) {
+	req, err := http.NewRequestWithContext(r.Context(), http.MethodGet, g.radarStatusesURL, nil)
+	if err != nil {
+		writeRadarFailed(w)
+		return
+	}
+	resp, err := g.radarHTTPClient.Do(req)
+	if err != nil {
+		writeRadarFailed(w)
+		return
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		writeRadarFailed(w)
+		return
+	}
+	ct := resp.Header.Get("Content-Type")
+	if ct == "" {
+		ct = "application/json"
+	}
+	w.Header().Set("Content-Type", ct)
+	w.WriteHeader(http.StatusOK)
+	_, _ = io.Copy(w, resp.Body)
+}
+
+func writeRadarFailed(w http.ResponseWriter) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.WriteHeader(http.StatusInternalServerError)
+	_ = json.NewEncoder(w).Encode(map[string]string{"error": "failed"})
+}
+
+// serveRadarPingDC — TCP :443 до каждого DC с таймаутом 2 с (аналог ping_proxy.php).
+func (g *Gateway) serveRadarPingDC(w http.ResponseWriter, r *http.Request) {
+	from := strings.TrimSpace(g.radarPingFrom)
+	if from == "" {
+		from = hostOnly(r.Host)
+		if from == "" {
+			from = "telemt-gateway"
+		}
+	}
+	results := make(map[string]map[string]any, len(telegramDC443))
+	for i := 1; i <= 5; i++ {
+		ip := telegramDC443[i]
+		addr := net.JoinHostPort(ip, "443")
+		t0 := time.Now()
+		conn, err := net.DialTimeout("tcp", addr, 2*time.Second)
+		ms := int(time.Since(t0).Milliseconds())
+		key := strconv.Itoa(i)
+		if err != nil {
+			results[key] = map[string]any{"ok": false, "ms": nil}
+			continue
+		}
+		_ = conn.Close()
+		results[key] = map[string]any{"ok": true, "ms": ms}
+	}
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.WriteHeader(http.StatusOK)
+	_ = json.NewEncoder(w).Encode(map[string]any{
+		"ok":      true,
+		"results": results,
+		"from":    from,
+	})
+}
+
+func hostOnly(hostPort string) string {
+	hostPort = strings.TrimSpace(hostPort)
+	if hostPort == "" {
+		return ""
+	}
+	// IPv6 в квадратных скобках: [::1]:8080
+	if strings.HasPrefix(hostPort, "[") {
+		if i := strings.IndexByte(hostPort, ']'); i > 0 {
+			return hostPort[1:i]
+		}
+	}
+	h, _, err := net.SplitHostPort(hostPort)
+	if err != nil {
+		return hostPort
+	}
+	return h
+}