fix(gameserver): answer UI-gating cmds the 4.6.51 client stalls on

First real-client session (2026-10-07 01:00) showed the client walking and
attacking but UI interactions stalling: ~120 CsReq dropped with no reply.

- auto-empty responder: any unknown CsReq with a Cmd-enum ScRsp pair now
  gets an empty ScRsp, except the danger families (GridFight/ChessRogue/
  EvolveBuild/ChimeraDuel/Jukebox/CycleScore) which must stay dropped
  (client Sync(nil) NREs on empty, per the Rust lessons)
- GetUnreleasedBlockInfo: the Endgame entry waits on this - 4.6.51 wire is
  CsReq 4190 -> ScRsp 4112 retcode tag 14 (the Rust build answered 4130,
  an id this client never sends)
- SetClientPaused acked (client pauses itself when opening menus/map)
- explicit handlers: TakeQuestReward, GetFirstTalkNpc, QuitBattle,
  GetMapRotationData (Amphoreus teleport pillars), GetPamSkinData,
  GetAllServerPrefsData/UpdateServerPrefsData, GetHeartDialInfo, GetPetData,
  GetShopList
- SendRaw now logs (dummy/raw replies were invisible in gameserver.log)
- cmdpairs.go: req->rsp id pairs generated from the Cmd enum (865 pairs),
  stable across message renames
- smoke test extended: 4190->4112 and SetClientPaused ack verified

internal/gameserver/session.go

@@ -164,6 +164,8 @@ func (s *Session) SendRaw(pkt *NetPacket) error {
 	if s.closed.Load() {
 		return nil
 	}
+	PacketLog(fmt.Sprintf("[PACKET SEND RAW] cmd_id: %d %s (len: %d)", pkt.CmdType, goproto.NameByCmdID[pkt.CmdType], len(pkt.Body)))
+
 	payload := pkt.Encode()
 
 	s.kcpMu.Lock()