docs(render): S3 chunk 4 fix round 1 — loop-shape weather pin, one weather gate, dead terrain-clip stack, sky drawn once

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

docs/research/2026-09-01-overhaul/s3-walk-ownership-map.md

@@ -730,6 +730,63 @@ DELETE (no retail counterpart):
 - the register: no row is added (every deletion removes an acdream-only
   rule); any KEEP item still lacking a CPU/GPU equivalence pin gets one.
 
+### 10.4 Chunk 4 fix round 1 (lead, 2026-09-03, after the three-lens review of `6ba4b0b87`; round 1 of the two the plan allows)
+
+Retail lens PASS. Build and renderer lenses FAIL on one blocking item plus
+real leftovers. Every item lead-verified.
+
+- **K1 — a once-per-frame weather pin that can fail (blocking).** The
+  replacement pin (`Assert.Single` over `DrawWeatherOnce` call sites) passes
+  with a `foreach` wrapped around the single call — the exact round-1
+  regression. IL-offset ORDER pins have now failed three times to be
+  discriminating; use a LOOP-SHAPE pin instead: with the existing
+  `CompiledCallGraph`/`CompiledBranch` reader, assert that NO backward branch
+  in `RetailPViewRenderer.DrawLandscapeDynamicsPhase` (a branch whose target
+  offset is lower than its own offset) spans the `DrawWeatherOnce` call's
+  offset. MUTATION: wrap the call in `foreach (var slice in
+  clipAssembly.OutsideViewSlices)` → the pin fails (quote it); restore.
+- **K2 — one weather gate for the print and the draw (minor).** The Collect-
+  time `OC` print fires on `ctx.WeatherGateOpen`; the Replay draw adds a
+  second condition (`clipAssembly.OutsideViewSlices.Length > 0`). Derive BOTH
+  from one predicate on the frame context (the walk's own "a landscape turn
+  ran with the weather gate open") so the transcript can never report a
+  weather turn the frame did not draw; pin: gate closed → neither; gate open
+  → both.
+- **K3 — delete the dead terrain-clip producer stack (minor).** No producer
+  writes the terrain clip any more: delete `IWorldPassSurface.SetTerrainClip`,
+  `RhiWorldPassSurface.SetTerrainClip`, `ClipFrame.SetTerrainClip` and their
+  unit test, `PrepareClipFrame`'s terrain-clip publish half, and the
+  TerrainClip UBO section binding if no shader reads it (verify: if the
+  terrain/sky shaders declare the section, keep the section bound as an
+  all-zero disabled block and say so).
+- **K4 — the sky is drawn ONCE, unclipped, like the terrain and the weather
+  (major, same rule).** `DrawWalkSky` still draws the sky dome per active view
+  under `BeginDoorwayScissor` + `BindTerrainClip` + `EnableClipDistances`.
+  Retail draws the sky once (`GameSky::Draw(sky, 0)` @0x0050633c) before the
+  blocks; aperture exactness for an interior root comes from the depth clear,
+  the exit seals and the interior repaint (§9 R4 / FW4 slice 6's own
+  argument). Draw it once at the Sky leaf, no scissor, no clip; then
+  `BeginDoorwayScissor`, `BindTerrainClip`, `EnableClipDistances`/
+  `DisableClipDistances` lose their last consumer — delete them with K3
+  (the `EnableClipDistances`/`DisableClipDistances` pair around the exit-seal
+  and punch draws is DIFFERENT: those are the kept translated clips — keep
+  those calls). Gate: the four-pose self-gate + the cathedral-arrival pose
+  show no sky through interior walls (the seals/repaint cover it).
+- **K5 — plan inventory (note).** The plan's S5 cleanup inventory still lists
+  the six `ACDREAM_PROBE_CATHEDRAL_*` flags — the lead updates the plan.
+- **K6 — the punch-fan equivalence pin runs through production (minor).**
+  Build the slice with `ClipFrameAssembler.Assemble` (the real
+  `outsideSlicesList.Add(new ClipViewSlice(slot, AabbOf(poly), planes))`
+  path) and read it back through `clipAssembly.OutsideViewSlices[i].Planes`,
+  not a hand-built `ClipViewSlice`.
+- **K7 — restore the look-in slot assertion (note).** Put back the deleted
+  `Assert.NotEqual(0u, clipSlot)` on a look-in slice (the exit-seal KEEP
+  reads `_clipFrame.GetSlotPlanes(slice.ClipSlot)`).
+- **K8 — the rain emitters now submit after the weather mesh (note).** Retail
+  imposes no order between acdream's two substitutes; state that in
+  `DrawWeatherOnce`'s comment so the order change is on record.
+- Gates: §10.3 unchanged; InstalledDat exactly the four known failures.
+
 ## 11. Chunk 1 contract — transcript kinds, fixtures, and the print-only emitter (lead, 2026-09-03; runs AFTER chunk 3, because `LC`/`SC` only exist once terrain is per cell)
 
 ### 11.1 What exists (verified in the tree at `542b049b`)