feat: SDWAN data plane + UDP punch port fix + TUN reader

SDWAN:
- protocol: add SDWANConfig/SDWANPeer/SDWANPacket structs, MsgTunnel type
- server: sdwan.go (JSON file store), sdwan_api.go (Get/Set/broadcast/route)
- server: push SDWAN config on login, announce peer online/offline events
- server: RouteSDWANPacket routes TUN packets between nodes via signaling
- client: TUN device setup (optun), tunReadLoop reads IP packets
- client: handle SDWANConfig/SDWANPeer/SDWANDel push messages
- client: apply routes (per-node /32 + broad CIDR fallback)

UDP punch fix:
- nat/detect: capture LocalPort from STUN UDP socket for punch binding
- client: pass publicPort + localPort through login and punch config
- coordinator: include PublicPort in PunchParams for both sides
- protocol: add PublicPort to LoginReq and ReportBasic

Other:
- server: use client-reported PublicIP instead of raw r.RemoteAddr
- server: update PublicIP/Port from ReportBasic if provided
- client: config file loading with zero-value defaults backfill
- .gitignore: exclude run/, *.pid, *.log, sdwan.json
- go.mod: add golang.org/x/sys for TUN ioctl

cmd/inp2ps/main.go

@@ -3,6 +3,7 @@ package main
 
 import (
 	"context"
+	"encoding/json"
 	"flag"
 	"fmt"
 	"log"
@@ -16,6 +17,7 @@ import (
 	"github.com/openp2p-cn/inp2p/pkg/auth"
 	"github.com/openp2p-cn/inp2p/pkg/config"
 	"github.com/openp2p-cn/inp2p/pkg/nat"
+	"github.com/openp2p-cn/inp2p/pkg/protocol"
 )
 
 func main() {
@@ -91,6 +93,31 @@ func main() {
 		w.Header().Set("Content-Type", "application/json")
 		fmt.Fprintf(w, `{"status":"ok","version":"%s","nodes":%d}`, config.Version, len(srv.GetOnlineNodes()))
 	})
+	mux.HandleFunc("/api/v1/sdwans", func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodGet {
+			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+			return
+		}
+		w.Header().Set("Content-Type", "application/json")
+		_ = json.NewEncoder(w).Encode(srv.GetSDWAN())
+	})
+	mux.HandleFunc("/api/v1/sdwan/edit", func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+			return
+		}
+		var req protocol.SDWANConfig
+		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+		if err := srv.SetSDWAN(req); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		w.Header().Set("Content-Type", "application/json")
+		_ = json.NewEncoder(w).Encode(map[string]any{"error": 0, "message": "ok"})
+	})
 
 	// ─── HTTP Listener ───
 	ln, err := net.Listen("tcp", fmt.Sprintf(":%d", cfg.WSPort))