Render unification cutover, Step A (additive, behavior-neutral until Step B). When PortalVisibilityBuilder.Build roots at the synthetic outdoor node, seed OutsideView with the full-screen NDC quad so ClipFrameAssembler yields a full-screen OutsideView slice and DrawInside's DrawLandscapeThroughOutsideView draws terrain/sky/scenery/weather as the node's shell — the same callback that already draws the doorway slice for an interior root looking out.
Keyed on a new explicit LoadedCell.IsOutdoorNode flag (set by OutdoorCellNode.Build), NOT a cell-id heuristic: production EnvCell ids are >= 0x100 but test fixtures use low interior ids, so an id test misfired on 4 existing PortalVisibilityBuilderTests.
Nothing roots at the node until Step B, so this is behavior-neutral. Tests: App 216/0 (2 new UnifiedFloodTests incl. the spec section 10 pure-outdoor regression guard + 2 OutdoorCellNode flag assertions).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Purely additive: creates the synthetic outdoor cell node that will serve as the
flood-graph root for the unified render pipeline. Each nearby building's exit
portal (OtherCellId==0xFFFF) is reversed into a portal pointing back into the
building, with its polygon transformed to world space and InsideSide flipped so
the outdoor half-space is "inside" the node. WorldTransform=Identity (portals in
world space). Mirrors retail's outdoor landcell that DrawInside(viewer_cell)
roots at (SmartBox::RenderNormalMode, decomp pc:92635). Nothing consumes this
yet — consumer wiring is Task 2.
2 new tests, 212 total passing, 0 regressions.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
