fix(runtime): name why a placement is parked and fail closed when it cannot resolve

Fixes #284 (plan S1).

A first-entry placement that could not be prepared returned
RetrySetupUnavailable and was re-Advanced every pump forever. Nothing counted
it, nothing named its cause, and nothing distinguished "waiting for something
that will arrive" from "waiting for something that never can". That is why
#281's 43 test failures presented as four unrelated symptoms across App and
Runtime instead of one cause, and why a stuck entity in the live client simply
never appears with no log line to follow.

Worse, the two causes were conflated: 670f307c's missing-world-frame park
reported itself as RetrySetupUnavailable, sending anyone diagnosing it to the
prepared-asset pipeline rather than to the absent local-player Create that
actually publishes the frame.

- RetryWorldFrameUnavailable splits the two causes. Call sites now ask
  IsRetryable() instead of comparing against one reason, so a future retry
  reason cannot be silently reclassified as a hard rejection - the exact way
  this class of bug hides.
- The operation retains its RuntimeSetPositionParkReason, and
  RuntimeSetPositionOwnershipSnapshot reports parked work by cause
  (ParkedAwaitingSetupCollisionCount / ParkedAwaitingWorldFrameCount /
  ParkedPlacementCount), so parked placements appear wherever ledgers are
  already asserted.
- ObserveLocalPlayerCreate records the accepted local-player Create even when
  it carries no landblock - precisely the case where no frame is ever
  published - and ThrowIfWorldFrameUnreachable makes that contradiction
  terminal. Waiting is legitimate only while that Create is outstanding; after
  it, no later pump can supply the frame. Same shape as 01f4791e, which made a
  violated receipt-ledger invariant terminal rather than resumable.

This is observability plus fail-fast. There is no timeout, no retry cap, and
no grace period anywhere in it; retryable work still retries exactly as before
and no placement behaviour changed.

The parked counts are deliberately NOT folded into IsConverged: #277 documents
a far Create legitimately parking for a whole session, so a parked entry at
teardown is not automatically a defect. Wiring them into the connected gates
is carried with #277's service-window conversion, where "legitimately parked"
becomes definable.

Runtime 1,012/1,012. Complete Release solution: 10,834 passed / 4 skipped /
0 failed.

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

src/AcDream.Runtime/Entities/RuntimeEntityObjectLifetime.cs

@@ -556,17 +556,17 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
         Func<RuntimeEntityRecord, Exception?>? retirePriorProjection)
     {
         EnsureNotDisposed();
-        if (beginInitialResidence
-            && isLocalPlayer
-            && (incoming.Physics?.Position ?? incoming.Position)
-                is { LandblockId: not 0u } initialPlayerPosition)
+        if (beginInitialResidence && isLocalPlayer)
         {
             // The accepted local Create establishes the shared world frame
             // before any remote first-entry conductor converts its authored
-            // landblock-local coordinates.
-            Physics.ObserveLocalWorldFrame(
-                initialPlayerPosition.LandblockId,
-                teleportAdvanced: false);
+            // landblock-local coordinates. #284: observe the Create itself
+            // even when it carries no usable landblock - that is precisely
+            // the case in which no frame is ever published, and every remote
+            // placement would otherwise park forever without a diagnostic.
+            Physics.ObserveLocalPlayerCreate(
+                (incoming.Physics?.Position ?? incoming.Position)
+                    ?.LandblockId ?? 0u);
         }
         if (_sessionClearInProgress)
         {

src/AcDream.Runtime/Entities/RuntimeRemoteFirstEntryState.cs

@@ -348,8 +348,10 @@ internal sealed class RuntimeRemoteFirstEntryState
                     gameTime,
                     out RuntimeSetPositionCommand command,
                     resolveWorldOffsetFromRuntimeFrame: true);
-            if (moverStatus
-                == RuntimeSetPositionMoverPreparationStatus.RetrySetupUnavailable)
+            // #284: every retryable reason resumes on a later pump. Comparing
+            // against one reason would silently reclassify a new one as a
+            // hard rejection.
+            if (moverStatus.IsRetryable())
             {
                 return RuntimeRemoteFirstEntryStatus.AwaitingCollisionSource;
             }

src/AcDream.Runtime/Gameplay/RuntimeLocalPlayerFirstEntryState.cs

@@ -364,8 +364,10 @@ internal sealed class RuntimeLocalPlayerFirstEntryState
                     collisionSource,
                     gameTime,
                     out RuntimeSetPositionCommand command);
-            if (moverStatus
-                == RuntimeSetPositionMoverPreparationStatus.RetrySetupUnavailable)
+            // #284: every retryable reason resumes on a later pump. Comparing
+            // against one reason would silently reclassify a new one as a
+            // hard rejection.
+            if (moverStatus.IsRetryable())
             {
                 return RuntimeLocalPlayerFirstEntryStatus
                     .AwaitingCollisionSource;

src/AcDream.Runtime/Physics/RuntimePhysicsState.cs

@@ -449,6 +449,7 @@ public sealed class RuntimePhysicsState : IDisposable
     private long _nextCollisionPreparationSequence;
     private ulong _collisionWorldAuthority = 1UL;
     private uint _worldFrameCenterLandblockId;
+    private bool _localPlayerCreateObserved;
     private readonly List<Action<RuntimeCollisionGenerationCommitted>>
         _collisionGenerationCommittedObservers = new();
     private bool _disposed;
@@ -545,6 +546,40 @@ public sealed class RuntimePhysicsState : IDisposable
         }
     }
 
+    /// <summary>
+    /// #284: records that this session's local-player Create was accepted,
+    /// independently of whether it carried a usable landblock. The frame is
+    /// published exactly once per session from that Create, so after it has
+    /// been observed a still-absent frame can never be supplied by a later
+    /// pump - see <see cref="ThrowIfWorldFrameUnreachable"/>.
+    /// </summary>
+    internal void ObserveLocalPlayerCreate(uint fullCellId)
+    {
+        EnsureNotDisposed();
+        _localPlayerCreateObserved = true;
+        ObserveLocalWorldFrame(fullCellId, teleportAdvanced: false);
+    }
+
+    /// <summary>
+    /// #284: converts an unresolvable world-frame wait into a loud failure.
+    /// Parking is legitimate only while the local-player Create is still
+    /// outstanding; once it has been accepted without publishing a frame,
+    /// every remote placement would retry forever in silence and the entities
+    /// would simply never appear. Terminal by design - this is a violated
+    /// invariant, not resumable work.
+    /// </summary>
+    internal void ThrowIfWorldFrameUnreachable(uint fullCellId)
+    {
+        if (!_localPlayerCreateObserved || _worldFrameCenterLandblockId != 0u)
+            return;
+
+        throw new InvalidOperationException(
+            "Runtime's world frame is unreachable: the local-player Create "
+            + "was accepted without publishing a frame, so the placement for "
+            + $"landblock 0x{fullCellId & 0xFFFF0000u:X8} can never resolve. "
+            + "A local-player CreateObject must carry a non-zero landblock.");
+    }
+
     /// <summary>
     /// Converts a retail landblock-local network frame into the Runtime's
     /// current world frame without consulting presentation or waiting for
@@ -1363,6 +1398,7 @@ public sealed class RuntimePhysicsState : IDisposable
         SetPosition.ResetSession();
         CollisionReports.ResetSession();
         _worldFrameCenterLandblockId = 0u;
+        _localPlayerCreateObserved = false;
         AdvanceCollisionWorldAuthority();
         Volatile.Write(ref _collisionMutationThreadId, 0);
     }
@@ -2056,6 +2092,7 @@ public sealed class RuntimePhysicsState : IDisposable
         _collisionAdmissions.Clear();
         _collisionGenerations.Clear();
         _worldFrameCenterLandblockId = 0u;
+        _localPlayerCreateObserved = false;
         CellCommitted = null;
         _collisionGenerationCommittedObservers.Clear();
         _disposed = true;

src/AcDream.Runtime/Physics/RuntimeSetPositionMoverPreparation.cs

@@ -9,11 +9,72 @@ namespace AcDream.Runtime.Physics;
 internal enum RuntimeSetPositionMoverPreparationStatus
 {
     Prepared,
+
+    /// <summary>
+    /// The authored Setup collision payload has not been read yet. Resolves
+    /// when the prepared-asset read completes.
+    /// </summary>
     RetrySetupUnavailable,
+
+    /// <summary>
+    /// #284: Runtime's world frame is not published yet, so a landblock-local
+    /// Create origin cannot be converted
+    /// (<see cref="RuntimePhysicsState.TryGetWorldFrameOffset"/>). Previously
+    /// this reported itself as <see cref="RetrySetupUnavailable"/>, which sent
+    /// anyone diagnosing a parked placement to the asset pipeline instead of
+    /// the missing local-player Create that actually publishes the frame.
+    /// Retryable exactly like Setup - only the reason differs.
+    /// </summary>
+    RetryWorldFrameUnavailable,
+
     RejectedAuthority,
     InvalidData,
 }
 
+internal static class RuntimeSetPositionMoverPreparationStatusExtensions
+{
+    /// <summary>
+    /// True for the statuses whose work can still succeed on a later pump.
+    /// Call sites must use this rather than comparing against one reason, so
+    /// a newly added retry reason cannot be silently treated as a rejection.
+    /// </summary>
+    internal static bool IsRetryable(
+        this RuntimeSetPositionMoverPreparationStatus status) =>
+        status is RuntimeSetPositionMoverPreparationStatus
+                .RetrySetupUnavailable
+            or RuntimeSetPositionMoverPreparationStatus
+                .RetryWorldFrameUnavailable;
+
+    /// <summary>
+    /// The parked-placement reason a retryable status contributes to the
+    /// ownership ledger, or <see cref="RuntimeSetPositionParkReason.None"/>
+    /// when the status is not a park.
+    /// </summary>
+    internal static RuntimeSetPositionParkReason ParkReason(
+        this RuntimeSetPositionMoverPreparationStatus status) =>
+        status switch
+        {
+            RuntimeSetPositionMoverPreparationStatus.RetrySetupUnavailable =>
+                RuntimeSetPositionParkReason.AwaitingSetupCollision,
+            RuntimeSetPositionMoverPreparationStatus
+                .RetryWorldFrameUnavailable =>
+                RuntimeSetPositionParkReason.AwaitingWorldFrame,
+            _ => RuntimeSetPositionParkReason.None,
+        };
+}
+
+/// <summary>
+/// #284: why a first-entry placement is currently parked. Retained on the
+/// operation so <c>CaptureOwnership</c> can report parked work by cause
+/// instead of leaving it invisible until a downstream symptom appears.
+/// </summary>
+internal enum RuntimeSetPositionParkReason
+{
+    None,
+    AwaitingSetupCollision,
+    AwaitingWorldFrame,
+}
+
 /// <summary>
 /// Distinguishes a Setup payload which has not arrived yet from a completed
 /// lookup whose result is absent. Retail supplies its dummy placement sphere

src/AcDream.Runtime/Physics/RuntimeSetPositionState.cs

@@ -273,8 +273,18 @@ internal readonly record struct RuntimeSetPositionOwnershipSnapshot(
     int AcknowledgedPlacementCompletionCount,
     int CollisionPrefixQuiescenceCount,
     int PendingQuiescenceProjectionCount,
-    int PooledOperationCount)
+    int PooledOperationCount,
+    int ParkedAwaitingSetupCollisionCount = 0,
+    int ParkedAwaitingWorldFrameCount = 0)
 {
+    /// <summary>
+    /// #284: placements that could not be prepared on their last attempt and
+    /// are waiting for a later pump, by cause. Non-zero at a stable
+    /// checkpoint means work is stuck; the reason names where to look.
+    /// </summary>
+    internal int ParkedPlacementCount =>
+        ParkedAwaitingSetupCollisionCount + ParkedAwaitingWorldFrameCount;
+
     internal bool IndexesConsistent =>
         LostDeadlineCount == LostDeadlineNodeCount
         && LostDeadlineCount == LostDeadlineIndexCount
@@ -399,6 +409,13 @@ internal sealed class RuntimeSetPositionState : IDisposable
         internal bool InheritedLostDeadline { get; set; }
         internal bool EnteringWorldFromCelllessResidence { get; set; }
         internal bool DormantLocalActivation { get; set; }
+
+        /// <summary>
+        /// #284: why this operation's mover preparation is currently parked,
+        /// or <see cref="RuntimeSetPositionParkReason.None"/> when it is not.
+        /// Observability only - it never gates work.
+        /// </summary>
+        internal RuntimeSetPositionParkReason ParkReason { get; set; }
         internal RuntimeSetPositionCommand? PreparedCommandAwaitingWithdrawalAck
         {
             get;
@@ -464,6 +481,7 @@ internal sealed class RuntimeSetPositionState : IDisposable
             InheritedLostDeadline = false;
             EnteringWorldFromCelllessResidence = false;
             DormantLocalActivation = false;
+            ParkReason = RuntimeSetPositionParkReason.None;
             PreparedCommandAwaitingWithdrawalAck = null;
             InPool = false;
         }
@@ -726,6 +744,8 @@ internal sealed class RuntimeSetPositionState : IDisposable
     {
         int deferred = 0;
         int awaitingPreparation = 0;
+        int parkedAwaitingSetup = 0;
+        int parkedAwaitingWorldFrame = 0;
         foreach (Operation operation in _operations.Values)
         {
             if (operation.Stage
@@ -735,6 +755,15 @@ internal sealed class RuntimeSetPositionState : IDisposable
             }
             if (operation.WakeableLostCell)
                 deferred++;
+            switch (operation.ParkReason)
+            {
+                case RuntimeSetPositionParkReason.AwaitingSetupCollision:
+                    parkedAwaitingSetup++;
+                    break;
+                case RuntimeSetPositionParkReason.AwaitingWorldFrame:
+                    parkedAwaitingWorldFrame++;
+                    break;
+            }
         }
         int pendingQuiescenceProjections = 0;
         foreach (CollisionPrefixQuiescence quiescence
@@ -764,7 +793,9 @@ internal sealed class RuntimeSetPositionState : IDisposable
             _acknowledgedPlacementCompletions.Count,
             _collisionPrefixQuiescence.Count,
             pendingQuiescenceProjections,
-            _operationPool.Count);
+            _operationPool.Count,
+            parkedAwaitingSetup,
+            parkedAwaitingWorldFrame);
     }
 
     internal int PendingProjectionCount => _pendingProjection.Count;
@@ -1518,8 +1549,10 @@ internal sealed class RuntimeSetPositionState : IDisposable
 
         if (!preparation.Setup.IsResolved)
         {
-            return RuntimeSetPositionMoverPreparationStatus
-                .RetrySetupUnavailable;
+            return Park(
+                operation,
+                RuntimeSetPositionMoverPreparationStatus
+                    .RetrySetupUnavailable);
         }
 
         RuntimeSetPositionMoverPreparation effectivePreparation = preparation;
@@ -1537,8 +1570,19 @@ internal sealed class RuntimeSetPositionState : IDisposable
                     out float worldOffsetX,
                     out float worldOffsetY))
             {
-                return RuntimeSetPositionMoverPreparationStatus
-                    .RetrySetupUnavailable;
+                // #284: the frame is published once, by the accepted
+                // local-player Create, and is never withdrawn inside a
+                // session. If that Create has already been observed, waiting
+                // is not a wait - no later pump can ever supply the frame, so
+                // parking here would retry forever in silence. Surface the
+                // contradiction instead, exactly as 01f4791e made a violated
+                // receipt-ledger invariant terminal rather than resumable.
+                _physics.ThrowIfWorldFrameUnreachable(
+                    authority.AcceptedPosition.LandblockId);
+                return Park(
+                    operation,
+                    RuntimeSetPositionMoverPreparationStatus
+                        .RetryWorldFrameUnavailable);
             }
 
             effectivePreparation = preparation with
@@ -1569,9 +1613,24 @@ internal sealed class RuntimeSetPositionState : IDisposable
             PreparedCommand = command,
         };
 
+        operation.ParkReason = RuntimeSetPositionParkReason.None;
         return RuntimeSetPositionMoverPreparationStatus.Prepared;
     }
 
+    /// <summary>
+    /// #284: records why this operation could not be prepared, so parked work
+    /// is visible in <see cref="CaptureOwnership"/> by cause rather than only
+    /// as a downstream symptom. Retains the reason on the operation until the
+    /// preparation succeeds or the operation is retired.
+    /// </summary>
+    private static RuntimeSetPositionMoverPreparationStatus Park(
+        Operation operation,
+        RuntimeSetPositionMoverPreparationStatus status)
+    {
+        operation.ParkReason = status.ParkReason();
+        return status;
+    }
+
     /// <summary>
     /// C0-3: chains the exact-Setup mover pipeline end-to-end for an
     /// authored placement (initial-Create or any other authored-mover