fix(streaming): stop replaying committed recenter retirements

Root cause: pending-only live projection buckets were misclassified as landblock presentation owners during origin recentering. That manufactured a second full cleanup receipt for a generation whose first receipt was still advancing; the duplicate guard threw and the broad retry path replayed the already-committed detach 243 times.

Keep pending live projections through the spatial identity map without issuing another receipt, and fail fast when a receipt-ledger invariant occurs after detachment. Evidence: docs/research/2026-08-02-collision-throughput-handoff/p1-retirement-receipt-loop.md. Release suite, lifecycle gate, and nine-stop soak pass.

src/AcDream.App/Streaming/LandblockPresentationPipeline.cs

@@ -322,8 +322,25 @@ public sealed class LandblockPresentationPipeline
     {
         GpuWorldRecenterRetirement detached =
             _state.DetachAllForOriginRecenter();
-        Exception? adoptionFailure =
-            _retirements.AdoptDetachedFull(detached.Landblocks);
+        Exception? adoptionFailure;
+        try
+        {
+            adoptionFailure =
+                _retirements.AdoptDetachedFull(detached.Landblocks);
+        }
+        catch (Exception error)
+        {
+            // Spatial detachment is already committed. A receipt-ledger
+            // invariant failure cannot be retried by detaching the same
+            // generation again; doing so was the 243-frame origin-recenter
+            // exception loop. Surface the committed edge so the controller
+            // fails fast instead of pretending the operation is resumable.
+            throw new StreamingMutationException(
+                "Origin-recenter retirement receipt adoption failed after " +
+                "the spatial generation detached.",
+                mutationCommitted: true,
+                error);
+        }
         Exception? failure = (detached.ObserverFailure, adoptionFailure) switch
         {
             (null, null) => null,