fix: skip Warden HASH_RESULT on strict servers when no CR match

Sending a wrong hash to AzerothCore/WotLK servers triggers an
account ban. When no pre-computed challenge-response entry matches
the server seed, skip the response entirely so the server times out
with a kick (recoverable) instead of verifying a bad hash and
banning (unrecoverable). Turtle/Classic servers remain unchanged
as they only log Warden failures.

Also adds RX silence detection and fixes Turtle isTurtle flag
propagation in MEM_CHECK path.

include/game/game_handler.hpp

@@ -3149,6 +3149,10 @@ private:
     std::future<std::vector<uint8_t>> wardenPendingEncrypted_;  // encrypted response bytes
     bool wardenResponsePending_ = false;
 
+    // ---- RX silence detection ----
+    std::chrono::steady_clock::time_point lastRxTime_{};
+    bool rxSilenceLogged_ = false;
+
     // ---- XP tracking ----
     uint32_t playerXp_ = 0;
     uint32_t playerNextLevelXp_ = 0;