feat(net+core): Phase 6.2 — honor server CurrentMotionState for idle pose

CreateObject's MovementData was being skipped past, so the renderer
always fell back to the MotionTable's default style/substate. That's
correct for most NPCs and characters but wrong for entities the
server explicitly puts into a non-default stance — most visibly the
Foundry's Nullified Statue of a Drudge, which the server sends with
a combat stance + Crouch ForwardCommand override and which therefore
rendered as an upright drudge instead of the aggressive crouched
statue you see on the retail client.

CreateObject.TryParse now extracts ServerMotionState (Stance +
optional ForwardCommand) from the inner MovementData. The header=false
layout was confirmed via ACE/.../WorldObject_Networking.cs:326 plus
MovementData.cs::Write and InterpretedMotionState.cs::Write. Only the
two fields the resolver needs are read; remaining InterpretedMotionState
bytes are skipped via the outer length so we don't have to handle
alignment of fields we don't care about.

MotionResolver.GetIdleFrame now takes optional stanceOverride and
commandOverride. Resolution priority is server-stance+command →
server-stance + style-default substate → MotionTable default. If the
composed cycle key doesn't resolve we fall back to the table default
rather than returning null, so a partial server override never makes
the entity worse than Phase 6.1.

160 tests green.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/AcDream.App/Rendering/GameWindow.cs

@@ -626,7 +626,17 @@ public sealed class GameWindow : IDisposable
         // the upright "Resting" pose instead of the Setup's Default
         // (T-pose / aggressive crouch). Static items with no motion table
         // get null and fall back to PlacementFrames in Flatten.
-        var idleFrame = AcDream.Core.Meshing.MotionResolver.GetIdleFrame(setup, _dats);
+        // Honor the server's CurrentMotionState (CreateObject MovementData)
+        // when present. The Foundry's drudge statue is the canonical case:
+        // its MotionTable's default style is upright "Ready" but the weenie
+        // is sent with a combat stance + Crouch ForwardCommand override, so
+        // resolving the cycle key from those gives the aggressive crouch.
+        ushort? stanceOverride = spawn.MotionState?.Stance;
+        ushort? commandOverride = spawn.MotionState?.ForwardCommand;
+        var idleFrame = AcDream.Core.Meshing.MotionResolver.GetIdleFrame(
+            setup, _dats, motionTableIdOverride: null,
+            stanceOverride: stanceOverride,
+            commandOverride: commandOverride);
         var flat = AcDream.Core.Meshing.SetupMesh.Flatten(setup, idleFrame);
 
         // Apply the server's AnimPartChanges: "replace part at index N