docs+cleanup: CURRENT-STATE.md and dead L86/L88 ablation switches removed (L131)

One current-state page (shipping behaviour, references with sources, gaps, verification, closed lines), linked from
CLAUDE.md. Removes the L86/L88 passage/boundary ablation switches and the unused legacy route-grade audit; inventory
of every kept switch in the report. Output identical: 24/24 + 18/18 hashes, fast tier, walk/seam audits, UE host
build; timing unchanged (-0.2%, CI spans 0). No Source/ changes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016dhxM43dnWvUu2B5Ph1iG1

ARCHITECTURE.md

@@ -1522,11 +1522,12 @@ collision ring became walkable at 0.632 s. `voxel.StreamingCoarseFirst=1` with
 residency by about one third on the staged plan, but null-RHI residency does not prove rendered
 enclosure. Keep coarse-first opt-in until that view is checked in a rendered owner-plan run.
 
-The separate `voxel.StreamingStartupApplyBoost` switch stays default-off. At `1`, it temporarily allows
-12 visible mesh submissions / 14 ms while the initial desired set and walkable ring are incomplete,
-with a 30 second ceiling; at `0`, the authored budget is unchanged. On the matched legacy-order test,
-the boost changed full-set readiness from 17.412 s to 17.346 s and removed count-cap frames, but did
-not improve end-to-end residency. Keep the normal 4 / 2 ms guard for play.
+The separate `voxel.StreamingStartupApplyBoost` switch is default-on in the current code. At `1`, it
+temporarily allows up to 24 visible mesh submissions / 14 ms while the initial desired set and
+walkable ring are incomplete, with a 30 second ceiling; at `0`, the authored budget is unchanged.
+The historical matched S6 run changed full-set readiness from 17.412 s to 17.346 s and removed
+count-cap frames, but did not improve end-to-end residency. These current defaults are defined in
+`Source/VoxelForge/Private/VoxelWorld.cpp`; the S6 measurement remains historical context.
 
 The S6 trace found the shared pool was not saturated: its 10-slot idle estimate was about 132
 slot-seconds on legacy order and 73 on gated coarse-first, while game-thread tile applies totaled only
@@ -1556,8 +1557,8 @@ by its RAII guard when the worker lambda exits. This still counts queued and run
 results do not consume an admission slot. `voxel.StreamingLegacyPendingResultCap=1` restores the old
 `PendingTiles` accounting; the test harness's `NearReserveMode=Legacy` also sets
 `voxel.StreamingDynamicNearReserve=0`, reproducing the S6 path. `StreamingDynamicNearReserve` now
-defaults to `1`; `StreamingCoarseFirst` remains `0`, and the apply boost remains `0` in the matched
-measurement.
+defaults to `1`; `StreamingCoarseFirst` remains `0`. That historical S6 matched measurement disabled
+the startup apply boost (`voxel.StreamingStartupApplyBoost=0`); the current default is on (§8.27).
 
 On the 2,578-key owner SurfaceWorld trace, the old-path control reached the full set in 17.527 s,
 walkable ring in 0.650 s, and full LOD0 in 2.281 s. Dynamic admission reached them in 7.780 s,