netcode-revival: verbose game-traffic telemetry on the relay

With --verbose, the relay logs a windowed summary of forwarded game
datagrams ('game traffic: N datagram(s) relayed to M member(s) in room
'XXX'') so the game's own RakNet netcode is observable in the relay log -
distinct from ghost pose joins. Counted per 2s window to avoid per-packet
spam.

src/native/skate3_native_ghost_relay.cpp

@@ -355,6 +355,7 @@ void GhostRelay::HandlePacket(const GhostAddr& from, const PacketBuf& p,
       GamePayload* fwd = reinterpret_cast<GamePayload*>(out.payload);
       fwd->src_virtual_ip = me->virtual_ip;
       const uint16_t size = PacketSize(out);
+      uint32_t recipients = 0;
       for (Client& c : clients_) {
         if (&c == me || c.refused) {
           continue;
@@ -367,6 +368,20 @@ void GhostRelay::HandlePacket(const GhostAddr& from, const PacketBuf& p,
           continue;
         }
         GhostSockSendTo(sock_, c.addr, &out, size);
+        ++recipients;
+      }
+      // Verbose: a windowed summary of game datagrams relayed, so the game's
+      // own netcode traffic is visible in the log.
+      if (verbose_.load(std::memory_order_relaxed) && recipients != 0) {
+        ++game_forwards_;
+        if (now - last_game_log_ >= 2.0 || game_forwards_ == 1) {
+          GHOST_RELAY_INFO("game traffic: {} datagram(s) relayed to {} "
+                           "member(s) in room '{}'",
+                           game_forwards_, recipients,
+                           std::string(me->room, me->room_len));
+          last_game_log_ = now;
+          game_forwards_ = 0;
+        }
       }
       break;
     }

src/native/skate3_native_ghost_relay.h

@@ -84,6 +84,11 @@ class GhostRelay {
   bool locked_ = false;
   char locked_room_[kGhostMaxRoomLen] = {};
   uint8_t locked_room_len_ = 0;
+  // Verbose game-traffic telemetry (netcode-revival): count forwarded game
+  // datagrams and log a windowed summary so the game's own RakNet traffic is
+  // observable without spamming the log per packet.
+  uint32_t game_forwards_ = 0;
+  double last_game_log_ = 0.0;
 };
 
 }  // namespace skate3::native_ghost