wip(assembler): round S12 -- short ready queue keeps workers fed between ticks: full set 6.0 s -> 4.9 s

voxel.StreamingReadyQueueDepth=8 admits one extra worker-set of prioritized
tasks; voxel.StreamingBackgroundWorkerCap=1 sizes slots to the 8 TaskGraph
background workers actually running tile tasks. Full set 5.96 -> 4.91 s,
LOD0 1.40 -> 1.09 s, ring 0.49 -> 0.51 s, 40 m/s ring 75/75. Tick p95
+0.6 ms spawn / +0.26 ms walk, max flat. No geometry change.
Report: Standalone/Research/WorldAssemblerM3/Round16.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MmSoF64BbRFmk9C3p1VsBJ

Source/VoxelForge/Public/VoxelWorld.h

@@ -137,6 +137,9 @@ struct FChunkResult
     // Les bornes de tâche incluent la conversion et la préparation du résultat autour du générateur.
     uint64 WorkerTaskStartCycles = 0;
     uint64 WorkerTaskEndCycles = 0;
+    // Operating-system thread id identifies the physical worker slot used by this tile.
+    // L'identifiant du thread systeme repere le slot worker utilise par cette tuile.
+    uint32 WorkerThreadId = 0;
     // Worker timing boundaries for separating scheduler wait from generation and result/apply wait.
     // These are captured with low overhead for the clean streaming-latency summary; expensive
     // per-tile profiling remains opt-in.
@@ -443,6 +446,7 @@ public:
      *  capped to (logical cores − 2) so small CPUs don't thrash on a flat 16 (background
      *  priority stops frame starvation, not the context-switch overhead). */
     int32 GetMaxConcurrentTasks() const;
+    int32 GetMaxConcurrentStreamingTasks() const;
     /** Submitted generation tasks still queued or running; completed MPSC results do not occupy admission.
      *  Taches de generation soumises, en file ou en cours ; les resultats MPSC termines ne bloquent pas l'admission. */
     int32 GetActiveGenerationTaskCount() const;
@@ -1239,6 +1243,7 @@ public:
     int32 ObsoleteTileAbortCount = 0;      // cumulative per-world moving-session cancellation count
     float PeakObservedPawnSpeedCmPerSecond = 0.0f;
     int32 EffectiveNearTaskReserve = -1;
+    bool bStreamingPlayerMoving = false;  // GT snapshot consumed by admission helpers / instantane GT pour les admissions
     uint64 NextStreamingRequestOrdinal = 0;
     std::atomic<uint64> NextStreamingGenerationOrdinal{0};
     // Cumulative worker-task wall cycles avoid aliasing the instantaneous per-frame counter.