docs(codemap): aligned clipmap rings, indexed reconcile, immediate gate support, two new tests

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

CODEMAP.md

@@ -312,7 +312,10 @@ casse cette arithmetique *structurellement* — `BeginPlay` loggue une **Error**
 | `SyncRemeshTile` | — | **INSTANT DIG**: level-0 same-frame re-mesh on the game thread (`GenerateTileResult` + `ApplyTileResult` inline, Cells=CHUNK_SIZE/Step=1 + strate band, no capture). Used for the tile under the brush centre so a carve is visible THIS frame; one full-res gen on the game thread. |
 | `UpdateChunksAroundPosition` | 362 | Builds desired set, cancels pending keys that left it, sorts from the **true pawn position**, submits the occupied/support LOD0 tile and the next tile along the pawn heading as an absolute `BackgroundHigh` prefix, then loads/unloads and handles LOD changes. **Delta cull**: `BuildDesiredTiles` returns the LEAVERS (stamped `DesiredStamped` map, one sweep) — only those + `TransitionHold` are considered per crossing, not every loaded tile. `BuildDesiredTiles` also applies `RenderDistanceChunks`: the outermost shell widens to cover the distance — as level-MaxClipLevel MC tiles, or (F18 `bFarSheetRing`) as a SHEET ring at level MaxClipLevel+span (covered-check vs the MaxClipLevel box; `VF_OuterShell` shared with `IsTileInClipRange` so the cull sees the same horizon), dz pre-clamped to the vertical band. **§9.3 anchors:** also prunes dead `StreamingAnchors` + detects their chunk crossings → rebuilds the desired set when an anchor moves/(un)registers (`bAnchorsMoved`/`bForceDesiredRebuild`), same cadence as player movement. §8.10. |
 | `AdvanceHeadlessCollisionGateStressTest` / `ObserveHeadlessCollisionGateStressTest` / `MaybeFinishHeadlessCollisionGateStressTest` | — | Explicit `-voxel.TestCollisionGateStress=1` harness only. The `GetDensityAt` column at capsule feet defines the local air/solid surface; each frame records actor position, velocity, direct foot tile and gate support readiness, gate state, signed feet clearance, and a ≤0.5-voxel sweep between positions. PASS requires no measured clearance below −5 cm; support submission/readiness, travel, and holds are diagnostics. Result logs include the terminal density column and the first crossing below spawn height. |
-| `BuildDesiredTiles` | ~722 | Builds `DesiredSorted`+`DesiredStamped` (player clipmap shells + F18 sheet ring) then `AddAnchorDesiredTiles()` before the leaver sweep; it orders from the true local pawn position and builds `CriticalDesiredTiles` for the occupied/support and heading tiles. |
+| `BuildDesiredTiles` | ~722 | Builds `DesiredSorted`+`DesiredStamped` (player clipmap shells + F18 sheet ring) then `AddAnchorDesiredTiles()` before the leaver sweep; it orders from the true local pawn position and builds `CriticalDesiredTiles` for the occupied/support and heading tiles. Also rebuilds `DesiredTransitionDescendants` (ancestor → desired descendants) for the reconcile pass. |
+| `VoxelClipmapDesiredTiles::Build` / `AlignedRingBounds` (`Private/VoxelClipmapDesiredTiles.h`) | — | The pure clipmap selector. **Every finer ring snaps outward to a child-pair boundary** (`AlignedRingBounds`, alignment 2; the last MC ring aligns to the sheet grouping width), so a coarser tile is wholly inside or wholly outside the finer ring: **no two desired tiles of different levels overlap** (a 7-wide odd ring used to leave one half-covered coarse tile per axis side, drawn over the fine one: 635 pairs at the owner config). Cost: LOD0 ring 343 → 512 tiles. Guarded by `VoxelForge.Streaming.ClipmapDesiredTilesNoOverlapCoverage`. Anchor tiles appended later are outside this guarantee. |
+| `ReconcileReadyTransitionVisibility` | — | Visibility-only pass while streaming is unsettled: hides a retired tile once all desired tiles over its footprint are loaded, reveals new tiles once no visible retired tile overlaps them. **Indexed** (dyadic ancestors + `DesiredTransitionDescendants`, visible retired tiles collected once per pass): moving p95 32 ms → 0.31 ms. `voxel.MeasureReadyTransitionVisibility=1` logs per-frame samples. |
+| `RequestCollisionGateSupportTile` / `UpdatePawnCollisionGate` | — | The gate submits the pawn's level-0 support tile **immediately** as `CollisionCritical`, even before the first desired set exists (the desired rebuild then adopts the same pending key). The gate holds downward Z only, with **no timeout** (the old 2 s release fired at every startup, while the game thread applied nothing for ~2.2 s). |
 | `AddAnchorDesiredTiles` | — | **§9.3 multi-anchor:** folds each `FVoxelStreamingAnchor`'s thin level-0 box (`XYRadiusChunks`/`ZBelowChunks`/`ZAboveChunks`) into the SAME desired set (deduped by stamp) so AI/remote players keep collision loaded around them; delta cull releases them on move/unregister. **§9.4:** a tile only a CollisionOnly anchor wants (clipmap didn't stamp it) → `CollisionOnlyTiles` → hidden at apply. Zero cost when no anchors. |
 | `ReconcileAnchorTileVisibility` | — | **§9.4:** after each rebuild, toggle `SetVisibility` on ALREADY-LOADED tiles that flipped render↔collision-only (diff `CollisionOnlyTiles` vs prev — bounded, no O(loaded) scan; unhide only if still desired). No-op without CollisionOnly anchors. |
 | `RegisterStreamingAnchor` / `UnregisterStreamingAnchor` | — | **BlueprintCallable §9.3:** add/remove an actor as a streaming anchor (`EVoxelAnchorPolicy` CollisionOnly/FullVisual + XY/ZBelow/ZAbove box). Idempotent; forces a rebuild next Tick. §9.4: CollisionOnly tiles cook collision but are hidden (no draw/VSM) unless the player clipmap wants them too. |
@@ -738,6 +741,8 @@ The plugin's first tests (`OPSTACK-PLAN.md` Phase 0.5). Run them from the editor
 | `VoxelForgePassageOpenSpaceTest.cpp` | `VoxelForge.Determinism.PassageLandsInOpenSpace` | Uses the real fixture density path to check both generated mouths against independent source queries, then audits all inter-strate landing ends: body-derived room dimensions, final-density flat-floor slope, local floor/join geometry, seal containment, hot-call/rebuild timing, and targeted `ClassifyTile` box soundness. Reports source-fit/refused mouths and per-archetype landing slopes; fails on any floor, join, seal, or box violation. |
 | `VoxelForgeStrateConnectivityTest.cpp` | `VoxelForge.Generation.StrateConnectivity` / `VoxelForge.Generation.StrateConnectivityRefinement` / `VoxelForge.Generation.VerticalShaftSeamFreedom` | Bounded strate metrics with density-polarity and solid-gap controls, deterministic route rechecks, and refinement sweeps. The refinement test uses the bounded 4-chunk density fixture, fits each measurement AABB to the arrival/departure mouth pair plus three shaft spacings (the prescribed local tree fallback), and caps the fitted control at 120,000,000 cells. It reports exact before/after seed-6 cell counts, reruns every negative with the fitted margin doubled, measures tree orphan candidates/path reachability and roughness-bubble proxies, asserts mouths remain inside the deterministic shaft feature core (the exact axis is an unsupported open cylinder), checks source/mirror physical paths, and requires 16/16 effective arrival→departure results across the 16 VerticalShafts seeds. Margin-binding negatives are reported as measurement limits, never as gap findings. The shaft seam test re-evaluates cell-boundary positions after warming distinct neighbouring chunk contexts. |
 | `VoxelForgeMazeSeamTest.cpp` | `VoxelForge.Generation.MazeSeamFreedom` | Re-evaluates **42** cell-boundary probes after warming six different neighbouring chunk contexts in both legacy and operator-stack paths. Latest result: **0 legacy mismatches, 0 operator mismatches**. The Maze source's 2×2×2 lower-node window is deliberately local; no wide collect is involved. |
+| `VoxelForgeClipmapNoOverlapTest.cpp` | `VoxelForge.Streaming.ClipmapDesiredTilesNoOverlapCoverage` | Sweeps 6,174 centres (negative coords, every parity) × radius/level/render-distance/vertical-clamp/sheet combinations: **zero overlapping desired pairs AND coverage ⊇ the frozen `7486c29` selector**. Failed on `7486c29` (1,022,679 overlapping pairs) as intended. |
+| `VoxelForgeDensityBlockEquivalenceTest.cpp` | `VoxelForge.Density.OperatorBlockMatchesScalarGrid` | Block evaluation (`EvalBlock` after `BuildActiveOpList` pruning) vs scalar, **bit-identical**: 5.1M mesher-grid samples (6 seeds × 8 archetypes × levels 0–5, with edits) + 300k direct `EvalBlock` samples. Scopes `voxel.UseFusedEvaluator=0` so the real block path runs. An injected optimistic `FPassageCarveOp::EffectOverBox` produced 5,612 mismatches. |
 | `VoxelForgeWorldEdgeSealTest.cpp` | `VoxelForge.Generation.WorldEdgeSeal` | Positive samples outside the radius across every fixture strate, bit-identical interior negative control against radius 0, monotonic smooth-ramp check, radius-0 no-op, radial `ClassifyBox`/T1.d proofs brute-forced for every reported voxel, and synthetic plus generated near-rim passage coverage. Emits one aggregate summary with proved-box and voxel counts. |
 
 ## 4. The density pipeline (most-edited hot path)