wip(assembler): round S11 -- bounded spawn apply budget: in-game full set 7.1 s -> 6.0 s

Startup apply mode on by default (12 meshes / 14 ms per frame, ends when the
initial set and walkable ring are ready, 30 s cap); normal play keeps the
authored budget. Backlog peak 252 -> 10, LOD8 apply wait 1.1 s -> 4 ms.
Ring 0.49 s, LOD0 1.40 s, 40 m/s ring 75/75. Remaining floor: frame-paced
admission (~8.3 submits/frame, 8 running workers max). No geometry change.
Report: Standalone/Research/WorldAssemblerM3/Round15.

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

CODEMAP.md

@@ -369,7 +369,7 @@ casse cette arithmetique *structurellement* — `BeginPlay` loggue une **Error**
 | `AdvanceHeadlessDigMotionTest` / `RecordHeadlessDigMotionFrame` | 3060 / 3217 | Explicit `-voxel.TestDigMotion=1` repro: optional near digs, then repeats underfoot digs and samples `Generator->GetDensityAt` immediately after each edit, on its first subsequent simulated frame, and on every following observation frame. `-voxel.TestDigMotionFieldOverride=1` is a measurement-only prototype that clears `CurrentFloor` and switches CMC to falling when the sampled post-edit density is air; it is inactive by default. The test counts false support, false air and downward velocity beyond one gravity step. `-voxel.TestDigMotionUnderfootDigCount` is clamped to 1–100; `-voxel.TestDigMotionUnderfootIntervalSeconds=0` performs per-frame rapid edits. The accompanying gap audit is scoped to the dig session. |
 | `MaybeFinishHeadlessStreamingTest` | — | The existing `voxel.TestExitSeconds` diagnostic emits `VoxelForgeStreamingExitDiag` at most every 30 elapsed seconds, including threshold and early-return test flags; no output when the timer is unconfigured. |
 | `UpdateVisualStalenessAudit` | 5034 | Test-only camera-frustum coverage audit: tracks up to 24 real pre-skirt isosurface points per visible component, then counts frames where no visible tile component covers a previously visible, still-desired point (excluding edited bounds). `voxel.TestVisualGapInjectEarlyHide=1` hides a valid component for three frames and must be caught. `voxel.TestGapAuditLegacyHandoff=1` restores old handoff culling for A/B baselines. |
-| `ProcessPendingChunks` | 7435 | Drains `CriticalProcessQueue`, `EditedProcessQueue`, `NearProcessQueue`, then `ProcessQueue` under the per-frame budget; reads the per-request cancellation token before removing its map entry, traces stale/obsolete/aborted discards with epoch and request ordinal, then applies each live result via `ApplyTileResult`. Collision profiling timestamps result arrival separately from game-thread apply wait. Step 1's `voxel.Step1PrequeueVisibleLOD0` still releases through this drain and emits `VFStep1UploadCorpusReleased`. |
+| `ProcessPendingChunks` | 7435 | Drains `CriticalProcessQueue`, `EditedProcessQueue`, `NearProcessQueue`, then `ProcessQueue`; applies under the authored 4-mesh/2 ms budget during normal play and the bounded shared startup budget (12 meshes/14 ms) until the initial desired set and walkable ring are ready. `voxel.StreamingStartupApplyBoost=0` restores the authored budget. `startup_apply_config` traces the actor-read CVar and both budgets; `startup_apply_budget` records activation/end. Reads per-request cancellation before removing its map entry, traces stale/obsolete/aborted discards with epoch and ordinal, then applies via `ApplyTileResult`. Step 1 prequeue still releases here and emits `VFStep1UploadCorpusReleased`. |
 | `ApplyTileResult` | — | **Shared game-thread apply** for one `FChunkResult` (async drain + sync carve): discards stale generation epochs and keys no longer desired, marks loaded, ingests capture, EMPTY releases the tile's existing component (a re-gen can flip content→empty on band change — old geometry must not linger), else `ApplyMeshToTile`. Returns true iff a visible mesh uploaded (counts the budget). Doesn't touch `PendingTiles` (caller's). |
 | `FVoxelStackSampler` / `FScopedVoxelStackRegistration` (`VoxelStackSampler.h/.cpp`) | — | **Diagnostic raw stack sampler, off by default.** A sampler thread captures registered generation workers' stacks (`CaptureThreadStackBackTrace`) every N µs and tags each with the tile's LOD. It writes bounded raw PCs to CSV plus a symbolization-free summary under `Saved/`; symbol resolution is deferred until after process exit so the measured process never initializes/calls DbgHelp for this diagnostic. Lifecycle teardown is serialized and registration TLS is session-tagged. Registration is per tile TASK in `LoadTile` (and the export's tasks), never per sample; disabled costs one relaxed atomic load. Game `-voxel.SampleStacks=<us>`, commandlet `-samplestacks[=us]`. |
 | Room-cache performance (2026-09-13): `VF_FindPlayerFitPointForRoomMemoized` / `GPlayerFitMemo` (`VoxelCaveMorphology.cpp`), `voxel.TileCacheWindow` + `VoxelGenLOD::TileOriginVoxels/TileCellsPerAxis` (`VoxelGenerator.h`), `FChunkSDFSpatialIndex` | — | **Player-fit memo:** exact 97-word key, process-wide, `voxel.PlayerFitMemo`. **Tile cache window:** the room cache covers the requesting tile's footprint plus a fixed collect margin. It is set via `TGuardValue` in `GenerateMesh`/classify, and is window-invariant by construction (the margin does not grow with the tile). **LOD-gated:** fused path at LOD ≥ `voxel.TileCacheWindowMinLOD` (3), op-stack at LOD ≥ `voxel.TileCacheWindowOpStackMinLOD` (4); lower LODs keep the 4-chunk worker window, because the tile window slowed LOD0 evaluation ~6%. Strates whose authored terrain ops exceed the proven 256-voxel extent (or are malformed/unloaded) fall back to the legacy window (`VF_ComputeTerrainOpEnvelope`). `voxel.SpatialIndex` is -1 auto (off at fused LOD0, on elsewhere), 0 or 1. **Spatial index:** ordered XY buckets over cache primitives, exact rejection. The `static_assert` in `VoxelStrateTypes.h` ties `VF_STRATE_PARAM_FIELDS` to `FStrateGenerationParams` (83 fields + 8 B padding). |