fix(physics): #345 — a grounded mover glides along a too-steep face; validate_walkable's return is scoped as retail's bytes scope it

Retail's OBJECTINFO::validate_walkable @0x0050d010 initializes its
return slot to OK (0x0050d025) and assigns ADJUSTED only inside the
below-plane guard, immediately after the push executes (0x0050d249).
The guard-fail path — grounded, OnWalkable, plane too steep — jumps
past the contact write, the push, and the assignment (0x0050d1b9 ->
0x0050d251): retail deliberately IGNORES the steep plane at primary
validation so the insert proceeds, the step-down phase fails on the
steep landing, and the edge family produces the per-tick lateral
glide. ACE flattened this into an unconditional return Adjusted
(ObjectInfo.cs:169) and we inherited it; our TransitionalInsert then
retried the byte-identical Adjusted forever — the user's
stop-instead-of-slide.

Evidence chain: the user's retail observation (the axiom), the live
cdb glide profile (edge_slide/cliff_slide 594 each in lockstep,
step_up 0), the D0 implementer's correct STOP (fixtures reproduced
the stuck fingerprint while faithfully executing the ACE-shaped
reading — refuting the reading, not the code), and the capstone
byte-decode both Opus reviewers re-derived independently, including
the stack-slot frame arithmetic and every ret site's eax.

The conformance fixture is the live topology: flat and steep terrain
triangles sharing ONE cell's diagonal (a cell-boundary face does NOT
reproduce the loop — the cell-scoped primary sample never validates a
neighbour's triangle — and is pinned as supplementary). Sabotage:
restoring the unconditional Adjusted reds the discriminator with the
exact stuck position (0.325 m lateral, 28/30 stuck ticks vs 2.602 m /
14/30 fixed; reviewer B's independent five-angle table is monotone
10-85 degrees). Stuck ticks are counted from positions so the
assertion survives the eventual probe strip.

In-game glide gate PASSED 2026-08-08: "Well it works, we are sliding.
I cant detect any speed change from retail."

Filed alongside: #347 + AD-70 (our glide alternates arm/move at half
retail's per-tick rate — retail redirects within the tick; next up by
user direction), AD-71 (the guard's mutable WalkableAllowance operand
vs retail's fixed is_valid_walkable global — now return-value-bearing),
and the reviewers' named residuals in the #345 closure entry
(placement-arm flip, other-cell coverage gap, EdgeSlide-less
projectiles, ACE's server-side shared misport predicting remote
drift-then-snap on steep terrain). The unported IsViewer arm of
validate_walkable is noted in the D0 doc.

Suite: clean-room complete solution 11,271 passed / 4 skipped / 0
failed; Core assembly re-run green after the review-driven test
hardening.

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

docs/architecture/retail-divergence-register.md

@@ -164,6 +164,8 @@ readiness/requeue adaptation. See
 | AD-67 | **Filed 2026-08-07 at the #32 closeout.** The narrowed `CollisionInfo.SetContactPlane` still writes `ContactPlaneCellId`, which retail's `COLLISIONINFO::set_contact_plane` @0x00509d80 does not — retail writes the cell id only in `CTransition::init_contact_plane` (@0x0050e8ca). Kept deliberately at the #32 fix on the research doc's own advice: acdream's consumers (the `[support]` probe's provenance, water-plane bookkeeping, `AdjustOffset`'s `ContactPlaneCellId != 0` gate) rely on the cell id being current per contact write, and retail's equivalent state travels a different route the port has not needed. | `src/AcDream.Core/Physics/TransitionTypes.cs` (`SetContactPlane`, the `ContactPlaneCellId = cellId` line) | The #32 fix removed the four LAST-KNOWN writes — the defect — and deliberately did not also change this contact-group field in the same commit; two behaviour changes in one fix would have made the user's cliff gate ambiguous. | A consumer that assumes the cell id changes ONLY at transition seed time (retail's timing) would observe it changing per contact write instead. No such consumer is known; `AdjustOffset`'s gate wants the current value. | `COLLISIONINFO::set_contact_plane` 0x00509d80 (22 bytes, no cell-id write); `CTransition::init_contact_plane` 0x0050e850 (cell id at 0x0050e8ca) |
 | AD-68 | **Filed 2026-08-07 at the #338 closure.** During an entity's ASYNC-RESIDENCY window — its flat Setup collision not yet resident — `LiveEntityMotionRuntimeController.GetSetupMoverShape` returns a placeholder mover shape: empty sphere list (falling back to the legacy 0.48/1.835 capsule reconstruction) and step heights **0.4/0.4**, values that appear nowhere in retail (authored human values are 0.600/1.500; retail's not-on-walkable fallback is 0.04). The local player has the same window between controller construction (0.4f defaults) and the publication candidate's adoption. Retail loads Setups synchronously and has no such window at all. Measured scale: 358 placeholder resolves vs 111,248 authored-pair resolves across one long session — seconds per entity, once. | `src/AcDream.App/Physics/LiveEntityMotionRuntimeController.cs` (`GetSetupMoverShape`, the `setup is null` and `<= 0f` arms); `src/AcDream.Runtime/Gameplay/PlayerMovementController.cs` (0.4f field defaults, adopted-over at publication) | An adaptation to async residency, not a wiring defect — #338's live probe proved prepare/publish/resolve all carry the authored values in steady state. Left as-is deliberately: shrinking the window is streaming work, not physics work. | A remote moving DURING its residency window steps 0.4 instead of its authored heights, and collides as a capsule instead of its sphere list — briefly, once per entity. If a future report says "an NPC stumbled on a stair right as it appeared", this row is the first suspect. | `CTransition::step_up` 0x0050b610 (0.04 fallback at 0x0050b655); `CPartArray::GetStepUpHeight` 0x005180d0; issue #338 |
 | AD-69 | **Filed 2026-08-07 at the S4 pseudocode pass (implementer finding, verified against the decomp).** `Transition.AdjustOffset`'s safety push-out computes `dist` WITHOUT the cell-relative correction retail applies: retail's `adjust_offset` (and ACE's port, independently) run the sphere centre through `LandDefs::get_block_offset` against the contact plane's own cell before the plane-distance dot, so a contact plane owned by a DIFFERENT landblock than the mover's current cell measures in the plane's frame. acdream dots the raw world-space centre against the stored plane. Same-landblock contact (the overwhelming case) is identical; a landblock-SEAM contact measures dist offset by the block delta, mis-firing or mis-suppressing the push-out at seams. | `src/AcDream.Core/Physics/TransitionTypes.cs` (`AdjustOffset`, the dist computation ahead of the push-out block) | Discovered during S4 but deliberately not folded in: S4's own AD-66 half was withheld the same night (#341), and a third change in the same block would have made the anomaly investigation unattributable. Fix alongside the AD-66 relanding. | A mover resting on a contact plane owned by the neighbouring landblock (seam walking) gets a push-out computed against a dist that is wrong by the block offset — either a spurious lift or a missed penetration correction, exactly at landblock seams, the #176/#177 symptom neighbourhood. | `CTransition::adjust_offset` 0x0050a370 (pc:272271-272393); `LandDefs::get_block_offset`; ACE `Transition.AdjustOffset` (cross-check); issue #341 (sequencing) |
+| AD-70 | **Filed 2026-08-08 with the #345 fix.** Our steep-slope glide alternates: the edge-family arming tick absorbs the request (zero yield) and only the next tick's `AdjustOffset` pre-projection moves, then the clean move clears the sliding normal — a strict two-tick cycle. Retail redirects WITHIN the tick (`edge_slide`/`cliff_slide` 594 each over a ~15 s live glide — every 30 Hz tick, lockstep with `set_sliding_normal` 538) and yields motion every tick. | `src/AcDream.Core/Physics/TransitionTypes.cs` (`EdgeSlideAfterStepDownFailed` + the insert's post-constraint continuation) | The #345 landing deliberately touched only `validate_walkable`'s return scoping; the response bodies were freshly user-gated (Campaign S) and AD-66 had just relanded in the same block. | Gliding along a too-steep face at ~half retail's lateral speed; direction and angle-scaling correct. Visible as "slides but slower than retail" in a side-by-side. | `345-retail-glide.cdb.log` counters; `Issue345SteepSlopeGlideTests` tick trace; issue #347 |
+| AD-71 | **Filed 2026-08-08 (reviewer finding on the #345 fix).** `ValidateWalkable`'s walkable test uses the MUTABLE `sp.WalkableAllowance` where retail's `validate_walkable` calls `CPhysicsObj::is_valid_walkable` @0x0050f530 — a FIXED global threshold (N.z >= [0x8ede5c], the walkable constant; the function reads no object state). Several code paths write `WalkableAllowance = LandingZ` (0.0871557 — TransitionTypes.cs:1688,2264, BSPQuery.cs:2330, FlatBspQuery.cs:2085) and `ClearWalkable()` does not restore it, so a stale-permissive value entering a grounded `!StepDown && OnWalkable` validate makes the guard PASS where retail's fails. Every override is permissive, so the #345 fix cannot REGRESS through this path — but for planes with N.z in (0.0872, 0.6642) a stale allowance leaves the old Adjusted-without-push dead loop reachable. The #345 landing GREW this row's blast radius: the operand now gates the return value (OK vs Adjusted), not merely the push (reviewer B, 2026-08-08). Also folds in: our `FloorZ = 0.6642f` vs ACE's 0.66417414f flips OK/Adjusted in a ~0.002-degree band. | `src/AcDream.Core/Physics/TransitionTypes.cs` (`ValidateWalkable`, the `walkable` guard operand) | Deliberately not folded into the #345 landing: the allowance plumbing is shared with the step-down family and needs its own conformance pass over every WalkableAllowance write/restore site. | A too-steep plane between LandingZ and FloorZ validated right after a placement/landing path that left the allowance permissive: the guard pushes+Adjusts where retail returns OK — the #345 stop, in a narrower band. | capstone decode of 0x0050f530 (reviewer A, 2026-08-08); `docs/research/2026-08-08-345-d0-branch-pin.md` flagged-secondary section |
 
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