Harden runtime against stutter-inducing log floods and missing display IDs

- Re-gate M2 glow diagnostics behind WOWEE_M2_GLOW_DIAG and DEBUG

- Deduplicate missing/failed texture warnings in asset and M2 texture loaders

- Deduplicate unhandled opcode warnings by state/opcode key in non-IN_WORLD phases

- Throttle malformed spline point-count warnings across world/classic/tbc parsers

- Ignore suspiciously huge display IDs from malformed packets with throttled warning

- Add nearest-known displayId model fallback cache for missing creature display mappings

- Clear display fallback caches on expansion reload and logout

src/game/game_handler.cpp

@@ -2823,19 +2823,24 @@ void GameHandler::handlePacket(network::Packet& packet) {
             // In pre-world states we need full visibility (char create/login handshakes).
             // In-world we keep de-duplication to avoid heavy log I/O in busy areas.
             if (state != WorldState::IN_WORLD) {
-                LOG_WARNING("Unhandled world opcode: 0x", std::hex, opcode, std::dec,
-                            " state=", static_cast<int>(state),
-                            " size=", packet.getSize());
-                const auto& data = packet.getData();
-                std::string hex;
-                size_t limit = std::min<size_t>(data.size(), 48);
-                hex.reserve(limit * 3);
-                for (size_t i = 0; i < limit; ++i) {
-                    char b[4];
-                    snprintf(b, sizeof(b), "%02x ", data[i]);
-                    hex += b;
+                static std::unordered_set<uint32_t> loggedUnhandledByState;
+                const uint32_t key = (static_cast<uint32_t>(static_cast<uint8_t>(state)) << 16) |
+                                     static_cast<uint32_t>(opcode);
+                if (loggedUnhandledByState.insert(key).second) {
+                    LOG_WARNING("Unhandled world opcode: 0x", std::hex, opcode, std::dec,
+                                " state=", static_cast<int>(state),
+                                " size=", packet.getSize());
+                    const auto& data = packet.getData();
+                    std::string hex;
+                    size_t limit = std::min<size_t>(data.size(), 48);
+                    hex.reserve(limit * 3);
+                    for (size_t i = 0; i < limit; ++i) {
+                        char b[4];
+                        snprintf(b, sizeof(b), "%02x ", data[i]);
+                        hex += b;
+                    }
+                    LOG_INFO("Unhandled opcode payload hex (first ", limit, " bytes): ", hex);
                 }
-                LOG_INFO("Unhandled opcode payload hex (first ", limit, " bytes): ", hex);
             } else {
                 static std::unordered_set<uint16_t> loggedUnhandledOpcodes;
                 if (loggedUnhandledOpcodes.insert(static_cast<uint16_t>(opcode)).second) {

src/game/packet_parsers_classic.cpp

@@ -126,7 +126,12 @@ bool ClassicPacketParsers::parseMovementBlock(network::Packet& packet, UpdateBlo
 
             uint32_t pointCount = packet.readUInt32();
             if (pointCount > 256) {
-                LOG_WARNING("  [Classic] Spline pointCount=", pointCount, " exceeds max, capping");
+                static uint32_t badClassicSplineCount = 0;
+                ++badClassicSplineCount;
+                if (badClassicSplineCount <= 5 || (badClassicSplineCount % 100) == 0) {
+                    LOG_WARNING("  [Classic] Spline pointCount=", pointCount,
+                                " exceeds max, capping (occurrence=", badClassicSplineCount, ")");
+                }
                 pointCount = 0;
             }
             for (uint32_t i = 0; i < pointCount; i++) {
@@ -1135,7 +1140,12 @@ bool TurtlePacketParsers::parseMovementBlock(network::Packet& packet, UpdateBloc
 
             uint32_t pointCount = packet.readUInt32();
             if (pointCount > 256) {
-                LOG_WARNING("  [Turtle] Spline pointCount=", pointCount, " exceeds max, capping");
+                static uint32_t badTurtleSplineCount = 0;
+                ++badTurtleSplineCount;
+                if (badTurtleSplineCount <= 5 || (badTurtleSplineCount % 100) == 0) {
+                    LOG_WARNING("  [Turtle] Spline pointCount=", pointCount,
+                                " exceeds max, capping (occurrence=", badTurtleSplineCount, ")");
+                }
                 pointCount = 0;
             }
             for (uint32_t i = 0; i < pointCount; i++) {

src/game/packet_parsers_tbc.cpp

@@ -140,7 +140,12 @@ bool TbcPacketParsers::parseMovementBlock(network::Packet& packet, UpdateBlock&
 
             uint32_t pointCount = packet.readUInt32();
             if (pointCount > 256) {
-                LOG_WARNING("  [TBC] Spline pointCount=", pointCount, " exceeds max, capping");
+                static uint32_t badTbcSplineCount = 0;
+                ++badTbcSplineCount;
+                if (badTbcSplineCount <= 5 || (badTbcSplineCount % 100) == 0) {
+                    LOG_WARNING("  [TBC] Spline pointCount=", pointCount,
+                                " exceeds max, capping (occurrence=", badTbcSplineCount, ")");
+                }
                 pointCount = 0;
             }
             for (uint32_t i = 0; i < pointCount; i++) {

src/game/world_packets.cpp

@@ -911,8 +911,14 @@ bool UpdateObjectParser::parseMovementBlock(network::Packet& packet, UpdateBlock
 
             uint32_t pointCount = packet.readUInt32();
             if (pointCount > 256) {
-                LOG_WARNING("  Spline pointCount=", pointCount, " exceeds maximum, capping at 0 (readPos=",
-                            packet.getReadPos(), "/", packet.getSize(), ")");
+                static uint32_t badSplineCount = 0;
+                ++badSplineCount;
+                if (badSplineCount <= 5 || (badSplineCount % 100) == 0) {
+                    LOG_WARNING("  Spline pointCount=", pointCount,
+                                " exceeds maximum, capping at 0 (readPos=",
+                                packet.getReadPos(), "/", packet.getSize(),
+                                ", occurrence=", badSplineCount, ")");
+                }
                 pointCount = 0;
             } else {
                 LOG_DEBUG("  Spline pointCount=", pointCount);