fix(animation): preserve wire motion on every spawn path

Replace the door-specific static-animation seed with one retail description-then-enter-world initializer shared by normal and reactive spawns. This preserves authoritative Dead and On/Off states, prevents replacement corpses from returning to Ready, and pins the lifecycle with Core and App tests.

Co-Authored-By: Codex <codex@openai.com>

tests/AcDream.App.Tests/Rendering/SpawnMotionInitializerTests.cs

@@ -0,0 +1,58 @@
+using AcDream.App.Rendering;
+using AcDream.Core.Net.Messages;
+using DatReaderWriter.DBObjs;
+using DRWMotionCommand = DatReaderWriter.Enums.MotionCommand;
+
+namespace AcDream.App.Tests.Rendering;
+
+public sealed class SpawnMotionInitializerTests
+{
+    [Fact]
+    public void CorpseUsesAuthoritativeDeadMotionFromWire()
+    {
+        var table = new MotionTable
+        {
+            DefaultStyle = (DRWMotionCommand)0x8000003Du,
+        };
+        var wire = new CreateObject.ServerMotionState(
+            Stance: 0x003D,
+            ForwardCommand: 0x0011);
+
+        SpawnMotionInitializer.Plan plan = SpawnMotionInitializer.ResolvePlan(table, wire);
+
+        Assert.Equal(0x8000003Du, plan.Style);
+        Assert.Equal(0x40000011u, plan.Motion);
+    }
+
+    [Theory]
+    [InlineData(0x000B, 0x4000000Bu)]
+    [InlineData(0x000C, 0x4000000Cu)]
+    public void DoorUsesAuthoritativeOnOrOffMotionFromWire(
+        ushort forwardCommand,
+        uint expectedMotion)
+    {
+        var table = new MotionTable();
+        var wire = new CreateObject.ServerMotionState(
+            Stance: 0x003D,
+            ForwardCommand: forwardCommand);
+
+        SpawnMotionInitializer.Plan plan = SpawnMotionInitializer.ResolvePlan(table, wire);
+
+        Assert.Equal(0x8000003Du, plan.Style);
+        Assert.Equal(expectedMotion, plan.Motion);
+    }
+
+    [Fact]
+    public void MissingWireStateUsesMotionTableDefaults()
+    {
+        var table = new MotionTable
+        {
+            DefaultStyle = (DRWMotionCommand)0x8000003Eu,
+        };
+
+        SpawnMotionInitializer.Plan plan = SpawnMotionInitializer.ResolvePlan(table, null);
+
+        Assert.Equal(0x8000003Eu, plan.Style);
+        Assert.Equal(0x41000003u, plan.Motion);
+    }
+}