refactor: split socket meta 'type' into config_type and nat_type — separate config (PUBLIC/NAT/PRIVATE) from detected NAT (EIM/STRICT/DIRECT) across NODEINFO, conn_mgr, route_bgp, route_node, etcpmon; win32 compat fixes (memmem, SHUT_WR, tun test_mode, tcp_proxy guards)

lib/platform_compat.h

@@ -30,6 +30,18 @@
     // POSIX functions missing on Windows
     #define strcasecmp _stricmp
     #define strncasecmp _strnicmp
+
+    // memmem — not available on Windows
+    #define memmem compat_memmem
+    static inline void* compat_memmem(const void* h, size_t hl, const void* n, size_t nl) {
+        if (nl == 0) return (void*)h;
+        if (hl < nl) return NULL;
+        const unsigned char* hay = (const unsigned char*)h;
+        const unsigned char* ndl = (const unsigned char*)n;
+        for (size_t i = 0; i <= hl - nl; i++)
+            if (hay[i] == ndl[0] && memcmp(hay + i, ndl, nl) == 0) return (void*)(hay + i);
+        return NULL;
+    }
     
     // poll() and pollfd are already defined in winsock2.h on MSYS2 UCRT64
     // Only define if not already present

lib/tcp_io.c

@@ -13,6 +13,9 @@
 #ifndef MSG_NOSIGNAL
 #define MSG_NOSIGNAL 0
 #endif
+#ifdef _WIN32
+#define SHUT_WR SD_SEND
+#endif
 
 static void read_cb(socket_t sock, void* arg);
 static void write_cb(socket_t sock, void* arg);
@@ -382,7 +385,7 @@ static void write_cb(socket_t sock, void* arg) {
     if (!tc->connected) {
         int err = 0;
         socklen_t len = sizeof(err);
-        if (getsockopt(tc->sock, SOL_SOCKET, SO_ERROR, &err, &len) == 0 && err == 0) {
+        if (getsockopt(tc->sock, SOL_SOCKET, SO_ERROR, (char*)&err, &len) == 0 && err == 0) {
             tc->connected = 1;
             DEBUG_DEBUG(DEBUG_CATEGORY_SOCKET, "tcp_io: connect ok fd=%d", (int)tc->sock);
         } else {