fix(R4-V5): #160 remote run movetos in slow motion - remote interps had no weenie, so retail's run-rate chain never reached my_run_rate

User observation (acdream observing a retail player's server MoveTo):
walk-distance approaches correct; run-distance plays the run cycle AND
moves toward the target in slow motion.

Root cause, raw-verified (apply_run_to_command 0x00527be0, raw
305062-305076): retail's rate chain is
  weenie ? (InqRunRate() ?: my_run_rate) : 1.0
Every placed retail object HAS a weenie; a REMOTE's weenie fails
InqRunRate (no local skill data) and the chain lands on my_run_rate -
the exact field retail's mt-6/7 unpack writes with the wire's
MoveToRunRate (M13; observed 4.50). Our port had the branch verbatim
but remote interps carried NO weenie at all, taking the else-1.0
branch retail reserves for weenie-less detached objects: observer-side
run dispatches went out at speed 1.0, so the run cycle's pace AND
get_state_velocity's chase speed both crawled. Walk was unaffected -
walk speed is never rate-scaled (the discriminating symptom).

Fix: RemoteWeenie (Core) - the minimal stand-in for retail's
per-object ACCWeenieObject: InqRunRate fails (-> my_run_rate),
InqJumpVelocity fails, IsThePlayer default false (also ends the
fragile "null weenie counts as the player" reading of the A3 dual
dispatch for remotes), IsCreature default true (doors carry it too;
their force-asserted Contact keeps the creature ground-gate moot -
documented on the class). RemoteMotion's interp now constructs with
it.

Tests: RemoteWeenieRunRateTests pins both branches against the raw -
RemoteWeenie + MyRunRate=4.5 promotes WalkForward->RunForward @ 4.5;
weenie-less keeps the verbatim degenerate 1.0. Full suite green: 3,963.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/AcDream.App/Rendering/GameWindow.cs

@@ -610,7 +610,15 @@ public sealed class GameWindow : IDisposable
                 // transition link (see PhysicsBody.InWorld).
                 InWorld = true,
             };
-            Motion = new AcDream.Core.Physics.MotionInterpreter(Body);
+            Motion = new AcDream.Core.Physics.MotionInterpreter(Body)
+            {
+                // R4-V5 #160 fix: retail remotes carry a weenie whose
+                // InqRunRate FAILS, landing apply_run_to_command on
+                // my_run_rate (the M13 wire feed). A null weenie took the
+                // degenerate 1.0 branch — observer-side run movetos played
+                // and moved in slow motion. See RemoteWeenie.
+                WeenieObj = new AcDream.Core.Physics.RemoteWeenie(),
+            };
         }
     }
 

src/AcDream.Core/Physics/RemoteWeenie.cs

@@ -0,0 +1,54 @@
+namespace AcDream.Core.Physics;
+
+/// <summary>
+/// R4-V5 (#160 fix, 2026-07-03): the minimal weenie every REMOTE entity's
+/// <see cref="MotionInterpreter"/> carries — standing in for retail's
+/// per-object <c>ACCWeenieObject</c>, which every placed physics object has.
+///
+/// <para>
+/// The load-bearing behavior is the RUN-RATE FALLBACK CHAIN:
+/// <c>apply_run_to_command</c> (0x00527be0, raw 305062-305076) reads
+/// <c>weenie ? (InqRunRate() ?: my_run_rate) : 1.0</c>. Remote weenies in
+/// retail FAIL <c>InqRunRate</c> (no local skill data), landing on
+/// <c>my_run_rate</c> — exactly the field the mt-6/7 unpack writes with the
+/// wire's <c>MoveToRunRate</c> (M13). Our remote interps previously had NO
+/// weenie at all, taking the degenerate <c>else 1.0</c> branch retail
+/// reserves for detached objects — so an observer-side moveto dispatched
+/// RunForward at speed 1.0 instead of the wire rate: the run cycle played
+/// in slow motion and the chase velocity crawled (walk was unaffected —
+/// walk speed isn't rate-scaled).
+/// </para>
+///
+/// <para>
+/// <see cref="IWeenieObject.IsThePlayer"/> stays default false — the A3
+/// dual dispatch routes remotes through apply_interpreted_movement, ending
+/// the fragile "null weenie counts as the player" reading of that gate.
+/// <see cref="IWeenieObject.IsCreature"/> stays default true; static
+/// animated objects (doors) also carry this weenie — retail would say
+/// non-creature there, but their RemoteMotion bodies force-assert Contact,
+/// so the creature ground-gate is satisfied either way (noted, not a
+/// behavior difference today).
+/// </para>
+/// </summary>
+public sealed class RemoteWeenie : IWeenieObject
+{
+    /// <summary>Remote objects have no local skill data — fail, so the
+    /// retail fallback chain lands on <see cref="MotionInterpreter.MyRunRate"/>
+    /// (the wire-fed rate).</summary>
+    public bool InqRunRate(out float rate)
+    {
+        rate = 0f;
+        return false;
+    }
+
+    /// <summary>Remotes never locally compute jump arcs (server-broadcast
+    /// VectorUpdate velocities drive them).</summary>
+    public bool InqJumpVelocity(float extent, out float vz)
+    {
+        vz = 0f;
+        return false;
+    }
+
+    /// <summary>Remotes never locally initiate jumps.</summary>
+    public bool CanJump(float extent) => true;
+}

tests/AcDream.Core.Tests/Physics/RemoteWeenieRunRateTests.cs

@@ -0,0 +1,52 @@
+using AcDream.Core.Physics;
+using Xunit;
+
+namespace AcDream.Core.Tests.Physics;
+
+/// <summary>
+/// R4-V5 #160 fix: retail's apply_run_to_command (0x00527be0) run-rate
+/// chain is <c>weenie ? (InqRunRate() ?: my_run_rate) : 1.0</c>. Remote
+/// weenies FAIL InqRunRate, landing on my_run_rate — the field the mt-6/7
+/// unpack writes with the wire's MoveToRunRate (M13). These pin that a
+/// RemoteWeenie-equipped interp scales the run promotion by MyRunRate
+/// (observer-side movetos ran in slow motion when the interp had no
+/// weenie and took the degenerate 1.0 branch).
+/// </summary>
+public class RemoteWeenieRunRateTests
+{
+    [Fact]
+    public void ApplyRunToCommand_RemoteWeenie_ScalesByWireRunRate()
+    {
+        var interp = new MotionInterpreter(new PhysicsBody())
+        {
+            WeenieObj = new RemoteWeenie(),
+            MyRunRate = 4.5f, // the mt-6 wire write (unpack @300603)
+        };
+
+        uint motion = MotionCommand.WalkForward;
+        float speed = 1.0f;
+        interp.apply_run_to_command(ref motion, ref speed);
+
+        Assert.Equal(MotionCommand.RunForward, motion);
+        Assert.Equal(4.5f, speed, 3);
+    }
+
+    [Fact]
+    public void ApplyRunToCommand_NoWeenie_KeepsRetailDegenerateBranch()
+    {
+        // Verbatim retail: a weenie-LESS (detached-class) object scales by
+        // 1.0 (raw 305062-305076 `else x87_r7 = 1f`). Production bodies all
+        // carry a weenie (player: PlayerWeenie; remotes: RemoteWeenie).
+        var interp = new MotionInterpreter(new PhysicsBody())
+        {
+            MyRunRate = 4.5f,
+        };
+
+        uint motion = MotionCommand.WalkForward;
+        float speed = 1.0f;
+        interp.apply_run_to_command(ref motion, ref speed);
+
+        Assert.Equal(MotionCommand.RunForward, motion);
+        Assert.Equal(1.0f, speed, 3);
+    }
+}