fix(client): restore retail interaction parity

Harden keyboard and camera routing, inventory and vendor interactions, chat/emotes, relog portal flow, and paperdoll rendering. Add retail research, connected gate coverage, and release-gate validation.

src/AcDream.Core/Physics/MotionInterpreter.cs

@@ -2269,8 +2269,9 @@ public sealed class MotionInterpreter : IMotionDoneSink
         if (PhysicsObj is null)
             return false;
 
-        bool grounded = PhysicsObj.TransientState.HasFlag(TransientStateFlags.Contact)
-                     && PhysicsObj.TransientState.HasFlag(TransientStateFlags.OnWalkable);
+        const TransientStateFlags groundedMask =
+            TransientStateFlags.Contact | TransientStateFlags.OnWalkable;
+        bool grounded = (PhysicsObj.TransientState & groundedMask) == groundedMask;
         if (!grounded)
             return false;
 

src/AcDream.Core/Physics/RawMotionState.cs

@@ -74,6 +74,32 @@ public readonly record struct RawMotionAction(
 /// </summary>
 public sealed class RawMotionState
 {
+    public RawMotionState()
+    {
+    }
+
+    /// <summary>
+    /// Deep snapshot used at retail's synchronous SendMovementEvent boundary.
+    /// The action FIFO is copied so animation completion cannot mutate a
+    /// packet that has already been requested.
+    /// </summary>
+    public RawMotionState(RawMotionState other)
+    {
+        ArgumentNullException.ThrowIfNull(other);
+        CurrentHoldKey = other.CurrentHoldKey;
+        CurrentStyle = other.CurrentStyle;
+        ForwardCommand = other.ForwardCommand;
+        ForwardHoldKey = other.ForwardHoldKey;
+        ForwardSpeed = other.ForwardSpeed;
+        SidestepCommand = other.SidestepCommand;
+        SidestepHoldKey = other.SidestepHoldKey;
+        SidestepSpeed = other.SidestepSpeed;
+        TurnCommand = other.TurnCommand;
+        TurnHoldKey = other.TurnHoldKey;
+        TurnSpeed = other.TurnSpeed;
+        _actions.AddRange(other._actions);
+    }
+
     /// <summary>Retail <c>current_holdkey</c> (ctor default HoldKey_None).</summary>
     public HoldKey CurrentHoldKey  { get; set; } = HoldKey.None;
     /// <summary>Retail <c>current_style</c> (ctor default 0x8000003D, NonCombat).</summary>