fix #174: RemoveLinkAnimations seam is HandleEnterWorld (strip + drain)

Retail CPhysicsObj::RemoveLinkAnimations (0x0050fe20) is a tailcall to
CPartArray::HandleEnterWorld (0x00517d70) -> MotionTableManager::
HandleEnterWorld (0x0051bdd0): remove_all_link_animations PLUS a full
pending_animations drain (while (head) AnimationDone(0)), each pop
relaying MotionDone so CMotionInterp pops its pending_motions node in
lockstep. acdream bound the seam to the bare sequence strip, so every
jump's LeaveGround removed the animations that queued manager nodes
were counting down on — orphaning them (NumAnims>0, anims gone) and
permanently damming BOTH queues. MotionsPending() then never drained
(probe round: last player pending=False at the first MovementJump
press; old jump motions still completing at rest minutes later) and
BeginTurnToHeading/BeginMoveForward's verbatim motions_pending gates
starved every armed moveto: ACE's mt-6 walk-to-door armed but the body
never walked (wire-proven, seqs 98-101); the close-range use turn
never completed so the deferred action was silently eaten. Doors only
worked on a fresh session (shallow queue).

Rebind both production sites (remote EnsureRemoteMotionBindings +
the player's EnterPlayerModeNow block) to Manager.HandleEnterWorld();
the sequencer wrapper was a pure passthrough so the manager call is a
strict superset. All six interp seam sites (LeaveGround, HitGround,
Dead, and the detached-object guards) are the same retail chain.
Harness mirrors updated; pins: Issue174LinkStripDrainTests (the seam
drains both queues; fresh motions queue and complete after). Suites:
Core 2535 / App 713 / UI 425 / Net 385 green.

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

tests/AcDream.Core.Tests/Physics/Motion/RemoteChaseEndToEndHarnessTests.cs

@@ -174,7 +174,10 @@ internal sealed class RemoteChaseHarness
             TurnStopped = () => ObservedOmega = Vector3.Zero,
         };
         Interp.DefaultSink = Sink;
-        Interp.RemoveLinkAnimations = Seq.RemoveAllLinkAnimations;
+        // #174: production binds the seam to Manager.HandleEnterWorld
+        // (strip + full queue drain, retail 0x0050fe20 → 0x0051bdd0) —
+        // the bare sequence strip orphaned pending manager nodes.
+        Interp.RemoveLinkAnimations = () => Seq.Manager.HandleEnterWorld();
         Interp.InitializeMotionTables = () => Seq.Manager.InitializeState();
         Interp.CheckForCompletedMotions = Seq.Manager.CheckForCompletedMotions;