feat: Adds robust speed hack detection and movement throttling (#2266)

## Summary

   Server-side movement throttle that prevents speed hacking while accurately identifying cheaters with detection of lagging connections.

   **Key features:**
   - Credit buffer (200ms) absorbs timing jitter from legitimate players
   - Movement queue handles larger bursts, draining at proper game-tick intervals
   - RTT measurement distinguishes network lag from speed hacks
   - Queue depth detection catches ACK-throttled speed hacks (going straight)

   ## How It Works

   **Throttle** (prevention): Movements arriving too early either consume credit or get queued. The queue drains at
   correct intervals, so speed hackers can't move faster regardless of what they send.

   **Detection** (identification): Combines multiple signals to identify cheaters:
   | Signal | What it catches |
   |--------|-----------------|
   | Queue depth ≥4 sustained | ACK-throttled speed hacks (client limits unacked moves to 5) |
   | Movement rate >1.05x | Direction-change speed hacks where timing is visible |
   | Stable RTT + high queue | Eliminates false positives from laggy players |

   **RTT-Aware Logic:**
   - Probes only sent to players actively moving (event-driven, not global loop)
   - Stable low-latency + problems = suspicious
   - Unstable/high-latency + problems = probably just lag, throttle handles it

   ## Configuration

   ```json
   {
     "movementThrottle.maxCredit": 200,
     "movementThrottle.softQueueLimit": 6,
     "movementThrottle.hardQueueLimit": 10,
     "movementThrottle.debugLogging": false
   }
   ```

Projects/UOContent/Commands/MovementDebugCommands.cs

@@ -0,0 +1,94 @@
+using Server.Commands;
+using Server.Network;
+using Server.Targeting;
+
+namespace Server.Commands;
+
+public static class MovementDebugCommands
+{
+    public static void Configure()
+    {
+        CommandSystem.Register("MovementDebug", AccessLevel.GameMaster, MovementDebug_OnCommand);
+        CommandSystem.Register("MovementStats", AccessLevel.GameMaster, MovementStats_OnCommand);
+
+        // Subscribe to speed hack detection events and broadcast to online staff
+        MovementThrottle.OnSpeedHackDetected += OnSpeedHackDetected;
+    }
+
+    private static void OnSpeedHackDetected(
+        NetState ns,
+        Mobile mobile,
+        float rate,
+        MovementThrottle.DetectionVerdict verdict,
+        string urgency)
+    {
+        if (mobile == null)
+        {
+            return;
+        }
+
+        var hue = urgency switch
+        {
+            "HIGH"   => 0x25, // Red
+            "MEDIUM" => 0x35, // Orange
+            _        => 0x3B  // Yellow
+        };
+
+        CommandHandlers.BroadcastMessage(
+            AccessLevel.Counselor,
+            hue,
+            $"[{urgency}] Speed hack: {mobile.RawName} ({ns.Account?.Username}) " +
+            $"Rate:{rate:F2} Verdict:{verdict} @ {mobile.Location} {mobile.Map?.Name}"
+        );
+    }
+
+    [Usage("MovementDebug")]
+    [Description("Target a player to toggle verbose movement logging for their connection.")]
+    private static void MovementDebug_OnCommand(CommandEventArgs e)
+    {
+        e.Mobile.BeginTarget(-1, false, TargetFlags.None, MovementDebug_OnTarget);
+        e.Mobile.SendMessage("Target a player to toggle movement debug logging.");
+    }
+
+    private static void MovementDebug_OnTarget(Mobile from, object obj)
+    {
+        if (obj is not Mobile target || target.NetState == null)
+        {
+            from.SendMessage("That is not a valid online player.");
+            return;
+        }
+
+        var ns = target.NetState;
+        ns.MovementLogging = !ns.MovementLogging;
+
+        var state = ns.MovementLogging ? "ENABLED" : "DISABLED";
+        from.SendMessage($"Movement debug logging {state} for {target.RawName}.");
+    }
+
+    [Usage("MovementStats")]
+    [Description("Target a player to see their current movement throttle state.")]
+    private static void MovementStats_OnCommand(CommandEventArgs e)
+    {
+        e.Mobile.BeginTarget(-1, false, TargetFlags.None, MovementStats_OnTarget);
+        e.Mobile.SendMessage("Target a player to view their movement stats.");
+    }
+
+    private static void MovementStats_OnTarget(Mobile from, object obj)
+    {
+        if (obj is not Mobile target || target.NetState == null)
+        {
+            from.SendMessage("That is not a valid online player.");
+            return;
+        }
+
+        var stats = MovementThrottle.GetMovementStats(target.NetState);
+
+        from.SendMessage($"--- Movement Stats for {target.RawName} ---");
+        from.SendMessage($"Rate: {stats.Rate:F3} ({stats.SampleCount} samples) | Verdict: {stats.Verdict} | Confidence: {stats.Confidence:P0}");
+        from.SendMessage($"RTT: avg={stats.AverageRtt}ms last={stats.LastRtt}ms var={stats.RttVariance} stable={stats.StableConnection} samples={stats.RttSampleCount}");
+        from.SendMessage($"Queue: depth={stats.QueueDepth} | Credit: {stats.MovementCredit}ms");
+        from.SendMessage($"Packet rate: {stats.CurrentPacketRate}/s (peak: {stats.PeakPacketRate}/s)");
+        from.SendMessage($"Burst: size={stats.BurstSize} gap={stats.PrecedingGap}ms | Sustained: {stats.SustainedSeconds}s");
+        from.SendMessage($"Debug logging: {(stats.DebugLogging ? "ON" : "OFF")}");
+    }
+}

Projects/UOContent/Engines/FeatureFlags/FeatureFlagManager.cs

@@ -964,7 +964,8 @@ public static class FeatureFlagManager
             // Server project flags
             "player_trading" => ServerFeatureFlags.PlayerTrading = enabled,
             "pvp_combat"     => ServerFeatureFlags.PvPCombat = enabled,
-            "bank_access"    => ServerFeatureFlags.BankAccess = enabled,
+            "bank_access"          => ServerFeatureFlags.BankAccess = enabled,
+            "speedhack_detection"  => ServerFeatureFlags.SpeedhackDetection = enabled,
 
             // UOContent flags
             "vendor_purchase"        => ContentFeatureFlags.VendorPurchase = enabled,

Projects/UOContent/Network/Packets/IncomingAccountPackets.cs

@@ -194,6 +194,9 @@ public static class IncomingAccountPackets
     {
         var version = state.Version = new ClientVersion(reader.ReadAscii());
 
+        // Record RTT if this is a response to our probe
+        state.RecordRttMeasurement();
+
         ClientVerification.ClientVersionReceived(state, version);
     }
 
@@ -204,6 +207,9 @@ public static class IncomingAccountPackets
         int type = reader.ReadUInt16();
         var version = state.Version = new ClientVersion(reader.ReadAscii());
 
+        // Record RTT if this is a response to our probe
+        state.RecordRttMeasurement();
+
         ClientVerification.ClientVersionReceived(state, version);
     }
 
@@ -270,7 +276,7 @@ public static class IncomingAccountPackets
 
         state.SendSupportedFeature();
 
-        state.Sequence = 0;
+        state.ResetMovementState();
 
         state.SendMobileUpdate(m);
         state.SendMobileUpdate(m);

Projects/UOContent/Network/Packets/IncomingMovementPackets.cs

@@ -91,23 +91,9 @@ public static class IncomingMovementPackets
 
         var dir = (Direction)reader.ReadByte();
         int seq = reader.ReadByte();
-        var key = reader.ReadUInt32();
+        var key = reader.ReadUInt32(); // FastWalkStack key - not used (not on EA servers)
 
-        if (state.Sequence == 0 && seq != 0 || !from.Move(dir))
-        {
-            state.SendMovementRej(seq, from);
-            state.Sequence = 0;
-        }
-        else
-        {
-            ++seq;
-
-            if (seq == 256)
-            {
-                seq = 1;
-            }
-
-            state.Sequence = seq;
-        }
+        // Delegate to MovementThrottle which has full context for timing validation
+        MovementThrottle.ValidateAndQueueMovement(state, from, dir, seq);
     }
 }

Projects/UOContent/Network/Packets/IncomingPlayerPackets.cs

@@ -360,7 +360,7 @@ public static class IncomingPlayerPackets
 
         from.SendEverything();
 
-        state.Sequence = 0;
+        state.ResetMovementState();
     }
 
     public static void PingReq(NetState state, SpanReader reader)