docs: re-retire AD-55 — its retirement was resurrected by an unrelated revert

The Sledding constant has been the byte-confirmed cos(10 deg) =
0.98480775f in production since 252e8068 (2026-07-30), which also struck
the register row. Five hours later a8a7d64b — reverting the UNRELATED
TS-4 commit 5e2be19b — restored this file's older hunk and resurrected
the un-struck row text while leaving the code fixed. The zombie row then
cost tonight's session a full duplicate byte-derivation: the stale row
said 0.99999536f was live, so the binary was re-read to prove what
252e8068's own commit message already contained verbatim.

Tonight's derivation note is corrected to what it actually is — an
independent confirmation of the week-old fix — and S5 collapses to this
bookkeeping: no code change, no feel gate owed; the user has been
playing on the fixed constant for a week.

Process rule filed to memory (feedback_register_revert_resurrection):
after any revert whose diff touches the register, re-verify EVERY row in
the touched hunks; and before acting on a row's 'our code does X' claim,
grep the cited file for the claimed expression first. AD section
51 -> 50 active rows.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/architecture/retail-divergence-register.md

@@ -62,7 +62,7 @@ accepted-divergence entries (#96, #49, #50).
 
 ---
 
-## 2. Adaptation (AD) — 51 active rows (AD-68 filed 2026-08-07 at the #338 closure — the async-residency placeholder mover shape (0.4/0.4 steps + capsule) has no retail counterpart because retail loads synchronously; AD-67 filed 2026-08-07 at the #32 closeout — the narrowed `SetContactPlane` keeps its per-write `ContactPlaneCellId`, which retail writes only at `init_contact_plane`; AD-49 filed 2026-08-06 at the #334 fix — the BSP part-array flood runs its outdoor cell rectangle at seed time rather than only from retail’s residency-gated walk, keeping both registration floods on one residency rule; AD-64 filed 2026-08-05 at the C5b architecture review's D1 fix — AD-60's W2 wire-cell REACHABILITY decision is expressed once per host because the two hosts run parallel non-shared inbound routes; the committed VALUE is single-sourced at `RuntimeEntityObjectLifetime.CommitWireCellRebucket`, and unification is filed as #324; AD-60 CORRECTED the same day — its surviving-channel enumeration presented "the local force path, the missile arm" as exhaustive when the entire no-window host belonged in it; AD-1 RETIRED 2026-08-05, C5a deletion sweep — the legacy outdoor demote/restore lift this row described was `PhysicsEngine.Resolve`'s own body, deleted with zero production callers; AD-42 DELETED 2026-08-04, C4 route 3 — its last surviving citation, the headless portal-arrival resync's two-call Resolve/ResolvePlacement split, was retired by the canonical `RuntimeAcceptedPositionDriveController` portal arm; AD-2 amended same route with the deferred-place timing adaptation, the T8 tolerated-overwrite note, and the leash-anchor nuance; AD-63 filed 2026-08-04, cancelled-park presentation rollback — the rollback restores every presentation registration the park's Withdraw removed EXCEPT the player's selection, which is user intent rather than a projection; AD-62 filed 2026-08-03, C4 route 2 round 2 — a deferred ForcePosition retired without committing is not re-applied and its ack is not sent; AD-61 filed 2026-08-02, C3c review round 1 — the #270 settle compression now covers the local player; AD-59/AD-60 filed 2026-08-02, continuation-executor slice)
+## 2. Adaptation (AD) — 50 active rows (AD-55 RE-RETIRED 2026-08-07 — its 2026-07-30 retirement at 252e8068 was collaterally resurrected by the a8a7d64b revert of the unrelated TS-4 commit; the code kept the cos(10°) fix throughout; AD-68 filed 2026-08-07 at the #338 closure — the async-residency placeholder mover shape (0.4/0.4 steps + capsule) has no retail counterpart because retail loads synchronously; AD-67 filed 2026-08-07 at the #32 closeout — the narrowed `SetContactPlane` keeps its per-write `ContactPlaneCellId`, which retail writes only at `init_contact_plane`; AD-49 filed 2026-08-06 at the #334 fix — the BSP part-array flood runs its outdoor cell rectangle at seed time rather than only from retail’s residency-gated walk, keeping both registration floods on one residency rule; AD-64 filed 2026-08-05 at the C5b architecture review's D1 fix — AD-60's W2 wire-cell REACHABILITY decision is expressed once per host because the two hosts run parallel non-shared inbound routes; the committed VALUE is single-sourced at `RuntimeEntityObjectLifetime.CommitWireCellRebucket`, and unification is filed as #324; AD-60 CORRECTED the same day — its surviving-channel enumeration presented "the local force path, the missile arm" as exhaustive when the entire no-window host belonged in it; AD-1 RETIRED 2026-08-05, C5a deletion sweep — the legacy outdoor demote/restore lift this row described was `PhysicsEngine.Resolve`'s own body, deleted with zero production callers; AD-42 DELETED 2026-08-04, C4 route 3 — its last surviving citation, the headless portal-arrival resync's two-call Resolve/ResolvePlacement split, was retired by the canonical `RuntimeAcceptedPositionDriveController` portal arm; AD-2 amended same route with the deferred-place timing adaptation, the T8 tolerated-overwrite note, and the leash-anchor nuance; AD-63 filed 2026-08-04, cancelled-park presentation rollback — the rollback restores every presentation registration the park's Withdraw removed EXCEPT the player's selection, which is user intent rather than a projection; AD-62 filed 2026-08-03, C4 route 2 round 2 — a deferred ForcePosition retired without committing is not re-applied and its ack is not sent; AD-61 filed 2026-08-02, C3c review round 1 — the #270 settle compression now covers the local player; AD-59/AD-60 filed 2026-08-02, continuation-executor slice)
 
 Recent retirements: AD-3/AD-4 retired 2026-07-31 by exact active/per-candidate
 visible-cell availability, full-catalog containment-root validation, and the
@@ -107,7 +107,7 @@ readiness/requeue adaptation. See
 |---|---|---|---|---|---|
 | ~~AD-53~~ | **RETIRED 2026-07-31 (Campaign P Slice 1B).** `Transition.CliffSlide` now consumes only `collision_info.last_known_contact_plane.N`, exactly as retail does. The invented `LastWalkablePlane -> LastKnownContactPlane -> UnitZ` fallback chain is gone; invalid/default or parallel data takes retail's degenerate `OK_TS` return. | `src/AcDream.Core/Physics/TransitionTypes.cs` (`CliffSlide`); `tests/AcDream.Core.Tests/Physics/RetailEdgeResponseOrderingTests.cs` | — | — | `CTransition::cliff_slide` pc:272397 (0050a6d0); `last_known_contact_plane` maintenance pc:272659-272668 (~0050ad07) |
 | ~~AD-54~~ | **RETIRED 2026-07-31 (Campaign P Slice 1B).** Every stored walkable polygon now routes unconditionally to `PrecipiceSlide`, including a plane steeper than `FloorZ`; the invented steep-walkable reroute to `CliffSlide` is gone. | `src/AcDream.Core/Physics/TransitionTypes.cs` (`EdgeSlideAfterStepDownFailed`); `tests/AcDream.Core.Tests/Physics/RetailEdgeResponseOrderingTests.cs` | — | — | `CTransition::edge_slide` pc:273001-273090 (0050b3d0) |
-| AD-55 | `calc_friction`'s Sledding slope-flatness test compares `GroundNormal.Z > 0.99999536f` (≈0.175° from flat); the raw retail decomp literally computes `__fcos(0.17453292519943295)` (= cos(10°) ≈ 0.984808) and compares that against `contact_plane.N.z` — physically very different tests (0.175° accepts only essentially-perfectly-flat ground; 10° accepts any modest slope) | `src/AcDream.Core/Physics/PhysicsBody.cs` (`calc_friction`, the Sledding near-flat branch) | Filed 2026-07-30 splitting AP-7's retirement (Campaign P Slice P2). Two hypotheses, neither confirmed this pass: (a) BN misdecompiled a raw float-constant load as an `__fcos()` call (a known BN artifact class), or (b) ACE's own port made an independent error and cos(10°) is correct. `0.99999536f` is kept provisionally — least churn, since it is what acdream's own prior (structurally unreachable) dead code already had — pending a live Ghidra decompile of `0050ee70` checking whether the FCOS opcode is real or a raw `FLD` of one of these two constants | Currently harmless in production: nothing sets `PhysicsState.Sledding` client-side (see #166 research), so this branch is unreachable either way. The moment a data-authored Sledding toggle exists, the wrong constant changes which slopes get the light 0.2f sled-friction override vs. the heavier default | `CPhysicsObj::calc_friction` pc:276694-276822 (0050ee70), the `__fcos(0.17453292519943295)` slope-flatness comparison; ACE `PhysicsObj.calc_friction` PhysicsObj.cs:2120-2141 (`0.99999536f`); `docs/research/2026-07-30-response-layer-edge-family-pseudocode.md` §1, §7 item 3 |
+| ~~AD-55~~ | **RETIRED 2026-07-30 at `252e8068` — and RE-RETIRED 2026-08-07 after a revert resurrected the row text.** The production constant has been the byte-confirmed `0.98480775f` (cos 10°) since `252e8068`, which also struck this row. Five hours later `a8a7d64b` — reverting the UNRELATED TS-4 commit `5e2be19b` — restored this file's older hunk and resurrected the un-struck row while leaving the code fixed. The zombie row then cost a full duplicate byte-derivation on 2026-08-07 (independent confirmation, identical result: qword [0x007c6b28] = π/18 exactly, live FCOS, threshold cos(10°) = 0.984807753; see `docs/research/2026-08-07-ad55-sledding-constant-byte-decode.md`). The old `0.99999536f` was ACE's error — the radian literal evaluated in degree mode — and acdream inherited then corrected it. **Process rule filed to memory: reverting any commit that touched this register must re-verify EVERY row the revert's register hunk touches, because whole-hunk reverts of single-line rows silently undo unrelated row edits.** Original text, retained: `calc_friction`'s Sledding slope-flatness test compares `GroundNormal.Z > 0.99999536f` (≈0.175° from flat); the raw retail decomp literally computes `__fcos(0.17453292519943295)` (= cos(10°) ≈ 0.984808) and compares that against `contact_plane.N.z` — physically very different tests (0.175° accepts only essentially-perfectly-flat ground; 10° accepts any modest slope) | `src/AcDream.Core/Physics/PhysicsBody.cs` (`calc_friction`, the Sledding near-flat branch) | Filed 2026-07-30 splitting AP-7's retirement (Campaign P Slice P2). Two hypotheses, neither confirmed this pass: (a) BN misdecompiled a raw float-constant load as an `__fcos()` call (a known BN artifact class), or (b) ACE's own port made an independent error and cos(10°) is correct. `0.99999536f` is kept provisionally — least churn, since it is what acdream's own prior (structurally unreachable) dead code already had — pending a live Ghidra decompile of `0050ee70` checking whether the FCOS opcode is real or a raw `FLD` of one of these two constants | Currently harmless in production: nothing sets `PhysicsState.Sledding` client-side (see #166 research), so this branch is unreachable either way. The moment a data-authored Sledding toggle exists, the wrong constant changes which slopes get the light 0.2f sled-friction override vs. the heavier default | `CPhysicsObj::calc_friction` pc:276694-276822 (0050ee70), the `__fcos(0.17453292519943295)` slope-flatness comparison; ACE `PhysicsObj.calc_friction` PhysicsObj.cs:2120-2141 (`0.99999536f`); `docs/research/2026-07-30-response-layer-edge-family-pseudocode.md` §1, §7 item 3 |
 | AD-46 | **LIVE. Reframed at Campaign V slice V11 (2026-07-29), when GL was deleted and the comparison that discovered this row ceased to exist.** Dense alpha-blended distant scenery (the treeline) may read slightly denser than retail's, because the anisotropic TAP PATTERN is implementation-defined and acdream's Vulkan driver does not tap identically to retail's D3D9 one. Both request the same sampler state — trilinear, clamp-and-repeat, the device's maximum anisotropy. **What changed at V11 is only the left-hand side of the comparison**: this was measured GL-vs-Vulkan (~15% of the pixels in the band), and it is now a Vulkan-vs-retail question against the D3D oracle in the last column. The measurement below is retained as the evidence that the residual is a tap pattern and not a bug, even though one of its two arms no longer exists. | `src/AcDream.App/Rendering/Wb/WorldTextureArray.cs` (`RhiWorldTextureArray.WorldArrayAnisotropy`); measured in plan §5.5.19, reframed §5.5.24 | Not assumed — narrowed by measurement while both backends still existed, on an offline capture with no session, no entities and both clocks pinned. Anisotropy 1 → 41,509 differing pixels in the tree band; anisotropy 16 (GL's value, and retail's `m_D3DCaps.MaxAnisotropy`) → 22,266, and the rest of the frame fell to 497 px of 563,200, i.e. 8.8e-04, inside the campaign's 0.001 threshold. The residual was not a sub-pixel shift (an integer shift search found none), not a sharpness change (high-frequency energy matched within 5%), and not depth precision (forcing Vulkan's window-depth range to GL's compressed [0.5, 1] moved it by 3%). Monotone improvement toward GL's own anisotropy with no knob left is what made it a driver property rather than a bug. | Distant foliage shimmers or reads denser than retail's. The class is confined to alpha-blended dense overlap: opaque terrain, roofs, walls, water, statics, the character and the whole retained UI are inside threshold. **Now unfalsifiable by self-differential** — with GL gone, the only way to retire this row is a side-by-side against the retail client, not against another acdream backend. | `RenderDeviceD3D::SetDefaultD3DStates @ 0x005a3800`, whose `SetSamplerState(stage, 0xA /* D3DSAMP_MAXANISOTROPY */, m_D3DCaps.MaxAnisotropy)` at `0x005a4230` is the value acdream requests |
 | AD-47 | **Filed at Campaign V slice V11 (2026-07-29); the campaign's risk register scheduled this row here.** Multisample resolve sample POSITIONS are unspecified by both the Vulkan and D3D9 specifications, so acdream's MSAA-on silhouette edges do not match retail's pixel-for-pixel even at the same sample count. acdream's strict pixel gates therefore run with MSAA forced OFF on every arm, and MSAA-on gets only a relaxed visual smoke. | `src/AcDream.App/RuntimeOptions.cs` (`ACDREAM_MSAA_SAMPLES`); forced to 0 in `tools/run-offline-pixel-gate.ps1` | Measured, not assumed: plan §5.5.16 compared two backends at 4x and found **8.83% of the frame differing — 81,359 px of 921,600 — essentially all of it hugging foliage and silhouette edges**, which is ninety-fold over the 0.001 gate threshold. That is two implementations' sample patterns, not a renderer divergence, which is why forcing MSAA off is what makes the remaining difference attributable rather than a threshold relaxation. | Edge quality on thin geometry (fence rails, foliage, distant railings) differs from retail at the sub-pixel level whenever MSAA is on, which is the ordinary player configuration. Because the gates run MSAA off, **a real regression confined to the multisample path would not be caught by them** — that is the actual exposure this row records. | D3D9 `D3DRS_MULTISAMPLEANTIALIAS` / `D3DMULTISAMPLE_TYPE` as set by `RenderDeviceD3D::SetDefaultD3DStates @ 0x005a3800`; retail's sample pattern is the driver's, exactly as ours is |
 | AD-48 | **Filed at Campaign V slice V11 (2026-07-29).** Presentation is paced by the Vulkan swapchain present mode (FIFO, i.e. VSync) or by a refresh-rate software pacer when uncapped, rather than by retail's D3D9 `Present` with its own frame-rate limiter. Frame delivery cadence, and therefore input-to-photon latency, is a property of our present path rather than a port of retail's. | `src/AcDream.App/RuntimeOptions.cs:98-100`; `src/AcDream.App/Rendering/Gpu/Vk/VulkanSwapchain.cs` | Retail's limiter and ours both bound the frame rate to the display; the simulation is fixed-step and clock-driven, so gameplay timing does not ride on presentation cadence. The uncapped path exists for measurement and is not the shipping default. | A pacing mismatch shows up as judder or input latency that differs from retail's feel without any visual difference in a captured frame — invisible to every pixel gate by construction. Issue **#235** (the capped/RDP jump-presentation cadence alias) is the known live instance of this class. | D3D9 `IDirect3DDevice9::Present`; retail's frame limiter in `RenderDeviceD3D` |