feat(render) Campaign FW3.2b-1: the walk frame driver

WalkFrameDriver executes one full static-content frame from the walk's
turns so GPU command-buffer order equals retail's walk order. One rule
does the interleaving: the accumulated OrderedDrawStream flushes
through SubmitOrderedStream immediately before EVERY non-stream draw
(sky, terrain slice, cell shell, punch fan, alpha barrier).

Turn script, all decomp-cited and two of them corrected in review:
- Interior flood: per cell IN FLOOD ORDER, shell first then contents
  (PView::DrawCells @0x005a4840: DrawEnvCell @0x005a4abe precedes
  DrawObjCellForDummies @0x005a4b0d).
- Landscape: sky once, terrain per active slice, then blocks
  far-to-near; per cell the building turn precedes the cell's outdoor
  statics (DrawSortCell @0x0059f140).
- Building (DrawBuilding @0x0059f2a0): the BLD probe event stays at
  entry, but the ENTIRE body - alpha barrier, portal passes, shell -
  sits inside retail's gfxobj[deg_level]!=0 gate @0x0059f2d3, and the
  order is FlushAlphaList @0x0059f30b -> the two-pass punch/look-in
  walk -> THEN the shell draw @0x0059f345. The driver review caught
  both the missing gate and a shell-before-punch inversion; fixed
  with the addresses cited.

Walk seam: three additive default-implemented IWalkEventSink hooks
(OnLandscapeCellTurn / OnBuildingTurn / OnBuildingShellTurn /
OnPunchGeometry) - every existing sink and all FW1 conformance
fixtures unchanged. WalkLandBlock gains LandblockId for the cell-id
encoding. Leaf draws go through IWalkFrameLeafRenderer so FW3.2b-2
wires the real renderers and the referee suite runs on fakes +
RecordingGpuDevice.

Flagged for FW3.2b-2/FW4 adjudication (documented in code):
FlushFartherThan(building distance) vs retail flush-all
FlushAlphaList(0f); terrain-before-statics within the landscape turn.

Suites: full Release build 0 warnings; Walk lane 200/1 skip;
InstalledDat Walk conformance 40/1 untouched; hermetic 6,752/0.

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

src/AcDream.App/Rendering/Walk/WalkLandscapeAssembler.cs

@@ -168,6 +168,9 @@ public sealed class WalkLandscapeAssembler
         int sideCellCount = SideCellCountForRing(RingOf(gx, gy));
         var block = new WalkLandBlock
         {
+            // Additive (Campaign FW3.2b-1): same (bx<<24 | by<<16) encoding
+            // BlockCoords decodes below — see WalkLandBlock.LandblockId.
+            LandblockId = (uint)bx << 24 | (uint)by << 16,
             SideCellCount = sideCellCount,
             MaxZ = data.MaxZ,
             MinZ = data.MinZ,