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)
         {