feat(render): S3 chunk 1 — print-only walk transcript, OH fixtures, offline signature diff

Campaign OVERHAUL S3 chunk 1 (docs/research/2026-09-01-overhaul/s3-walk-ownership-map.md
§11): the transcript-kinds/fixtures/print-only-emitter half of the walk work,
built AFTER chunk 3 landed LC/SC (the per-land-cell interleave).

B1 — the emitter (print-only, never gates admission/depth/order):
- ACDREAM_DUMP_WALK_TRANSCRIPT=1 is read once into RuntimeOptions.DumpWalkTranscript
  (rule 4) and handed to RenderingDiagnostics.DumpWalkTranscriptEnabled (rule 5,
  a settable static, not a second env read) once at GameWindow construction — the
  deep walk call sites have no reachable RuntimeOptions reference.
- WalkTranscriptDump (new) prints the OH line kinds — F/P/LS/LC/SC/BLD/DI/DC/EC/OC —
  to Console at the exact points retail's cdb breakpoints sit
  (tools/walk-oracle/oh/oh-capture-walk.cdb.template), gated internally so every
  method bails out before any string work when the flag is off.
- Every call site lives in WalkFrameDriver.cs, at the point the driver already
  processes that turn: Collect (F/P, after BeginFrame), Emit's DI/LS/DC/BLD cases,
  OnLandCellTurn/OnLandscapeCellTurn (LC/SC, at LOD resolution via the new
  WalkTranscriptDump.LodCellId helper, before the 8x8-bucket expansion), and the
  EmitFloodTurns/EmitCellContentsTurn loops (EC/OC — both UNCONDITIONAL per flood
  visit, matching the OH captures' always-equal EC/OC counts; retail's own
  DrawEnvCell stamp dedupe sits past the breakpoint, inside the function).
- DC's "pv=" field encodes interior(0)/outdoor(1) as an 8-hex-digit 0/1 so it
  satisfies the same pv=[0-9a-f]{8} regex real captures use; derived from
  _currentDcStage at the DC event (CellStatic = interior pview, else outdoor).
- The frame-root pose (origin, quaternion) is a reasonable orthonormal basis built
  from the walk's own CyPlane.Normal forward vector and WalkLandscape's own
  ViewerWorldOriginX/Y block origin — self-consistent for the round-trip parser,
  not a byte-exact reproduction of retail's Frame (B4's diff never compares P).

B2 — WalkOracleTrace learns EC/OC event kinds (LC/SC already existed from chunk 3).
New WalkOraclePartsTrace.cs holds two small read-only parsers for the parts log
(PD/DM) and the alpha-depth log (AM/FL/PM/PC) — records only, no validator, no
canonical JSONL, no new tool.

B3 — fixtures: the five OH walk captures join WalkOracleTraceTests.AllFixtures
(now (root, name) pairs — FW0's own root plus the OH capture directory) for
parse + complete-frame pins. The four kit poses join WalkTraceConformanceTests'
still-fixture coverage as NEW rows (the OH cathedral-arrival root is f4180108,
not FW0's f4180106): terrace-edge/cathedral-arrival extend the existing theory
(now (root, fixture) parameterized); holtburg-doorway-still and foundry-deep get
dedicated tests mirroring their FW0 siblings' own structure. Finding: the OH
foundry-deep capture's own retail transcript draws 12 real town buildings through
its exit chain (unlike the FW0 capture, which apparently reached none at that
pose) — the FW0 test's stub 1x1 landscape undershoots it (first divergence:
nothing after "LS" vs retail's real BLD content); fixed by building the full
landscape/building world via WalkLandscapeDatBuilder.Build, matching the shared
theory's own approach, not by skipping or weakening the row.
WalkTraceReplayContext.Signature(WalkOracleFrame) now filters to the DI/DC/BLD/LS
kinds (LC/SC/EC/OC never had a WalkEvent analogue in RetailFrameWalk's own
four-kind vocabulary) instead of mapping them to a "?" placeholder, so the still-
fixture comparison stays apples-to-apples on both sides.

B4 — WalkTranscriptSignatureDiff (test-side only, no runner/tool): diffs two
transcripts (raw lines or parsed frames) at the full DI/DC/BLD/LS/LC/SC/EC/OC
level, reporting the first divergent event and position per frame. Proven over a
synthetic self-vs-self-minus-one-event pair (SignatureDiff_ReportsTheExactRemovedEvent).

Tests: T1 (flag off) is split into a unit-level zero-allocation/zero-output check
on WalkTranscriptDump itself (the walk's pre-existing allocation, e.g.
RetailFrameWalk.EmitDrawCells's per-call array, is untouched by this chunk and not
independently zero-alloc) and an integration-level Collect() check; both assert via
WalkOracleTrace.Parse returning zero frames rather than raw string equality, which
is robust to unrelated Console.WriteLine noise from other test classes running in
parallel (a real, observed hazard — WalkFrameDriverTests joins
CameraDiagnosticsCollection for the same reason CornerFloodReplayTests/
Issue181WallPressEquilibriumTests already do, issue #251). T2 proves the
emitter/parser round trip on a synthetic interior frame. T3's InstalledDat rows all
pass. T4: LaunchOptionsDocumentationTests green with the ACDREAM_DUMP_WALK_TRANSCRIPT
row (both directions).

Gates: hermetic lane 6,814/0 (was 6,795 baseline + new tests), three consecutive
clean runs; InstalledDat lane 245/3 known-failures (the two pre-existing #383
layout tests + TowerAscent) unchanged from baseline.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

docs/launch-options.md

@@ -272,6 +272,7 @@ $env:ACDREAM_FRAME_HISTORY            = "$scratch\frames.csv"
 | `ACDREAM_DUMP_GFXOBJS_DIR` | `=<dir>` | overrides the output directory for `ACDREAM_DUMP_GFXOBJS` — Companion output-directory knob for ACDREAM_DUMP_GFXOBJS. | print/file-path only; no effect unless `ACDREAM_DUMP_GFXOBJS` is also set | off/unset | `PhysicsDiagnostics.ProbeDumpGfxObjsPath` |
 | `ACDREAM_DUMP_SKY` | `=1` | Print-only: dumps decoded `SkyDesc` raw values on region load (`SkyDescLoader.cs`) and per-GfxObj `Surface.Type`/translucency flags on first upload (`SkyRenderer.cs`), plus gates a `TimeSync` console diagnostic in `GameWindow`. Built to resolve specific open questions about retail sky units and GfxObjReplace timing (2026-04-23 research), now answered but the dumps remain wired. — Generic sky-keyframe isolation dump (introduced with the phase-1 tint revert); a tool, not a bug probe. | Three independent reads of the SAME env var, only one of which (`RuntimeOptions.DumpSky`) goes through the typed options object; the other two are raw scattered reads (see Notes). `SkyRenderer.cs:582`'s raw read is in the App layer and has no architectural excuse for bypassing `RuntimeOptions` — `_options.DumpSky` was already available to that composition. `print-only` in all three sites. | off/unset | `RuntimeOptions.DumpSky` (typed) → `GameWindow.cs:704` (`TimeSyncDiagnostic`); **also** two independent raw `Environment.GetEnvironmentVariable` reads at `SkyDescLoader.cs:392` (Core) and `SkyRenderer.cs:582` (App) |
 | `ACDREAM_DUMP_STEEP_ROOF` | `=1` | gates `[steep-roof] KILL-VELOCITY-APPLIED` in `PhysicsEngine.ResolveWithTransition` when retail's `kill_velocity` zeroes body velocity on steep-slope impact, plus per-frame plane-normal traces in `TransitionTypes`/`PlayerMovementController` — KEEP: observes LIVE divergence-register row AD-56 (the plumb-fall freeze on steep-but-walkable polys, restored 2026-08-07). The only runtime lens on that active divergence; delete only with the AD-56 row itself. | print-only | off/unset | `PhysicsDiagnostics.DumpSteepRoofEnabled` |
+| `ACDREAM_DUMP_WALK_TRANSCRIPT` | `=1` | Campaign OVERHAUL S3 chunk 1 (§11.2 B1): the production frame walk (`RetailFrameWalk` + `WalkFrameDriver`) prints the OH oracle-trace line kinds — `F`/`P`/`LS`/`LC`/`SC`/`BLD`/`DI`/`DC`/`EC`/`OC` — to `Console.Out` at the exact points retail's cdb breakpoints sit (`tools/walk-oracle/oh/oh-capture-walk.cdb.template`), so a Release run's own transcript can be diffed offline against a live retail capture (frame-by-frame, at the DI/DC/BLD/LS/LC/SC/EC/OC level — the test-side `WalkTranscriptSignatureDiff` helper does the diff, not this flag). | print-only; every print sits AFTER the walk has already decided to emit the corresponding turn — never gates admission, depth state, or draw order. Off, the emitter (`WalkTranscriptDump`) does no string work and allocates nothing (`WalkFrameDriverTests.TranscriptEmitter_FlagOff_EveryPrintMethodIsAZeroCostNoOp`). | off/unset | `RuntimeOptions.DumpWalkTranscript` (typed, sole env read) → `GameWindow.cs` (one-time handoff at construction) → `RenderingDiagnostics.DumpWalkTranscriptEnabled` (the actual gate every call site checks) → `WalkTranscriptDump` / `WalkFrameDriver.cs` |
 | `ACDREAM_HIDE_PART` | `=<int>` | Hides one mesh part by index on entities with ≥10 parts (humanoids) — a debugging aid for equipment/clothing part-visibility issues. — Generic model-part isolation tool (issue #37 lineage but general-purpose since); a tool, not a bug probe. | Real (visible) behavior change, not print-only, but scoped to a single diagnostic index and off by default. | off/unset | `RuntimeOptions.HidePartIndex` → `LivePresentationComposition.cs:608` → `LiveEntityAnimationPresenter.cs:21,38,243` |
 | `ACDREAM_PROBE_CELL` | `=1` | gates one `[cell-transit]` line per `PlayerMovementController.CellId` change (old→new cell, position, reason tag) — Standing cell-transit tracer (L.2a slice 1), pair of the permanent ACDREAM_PROBE_RESOLVE; recurs in every membership investigation. | print-only; low volume (only on actual cell crossings) | off/unset | `PhysicsDiagnostics.ProbeCellEnabled` |