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>
TDD characterisation test proving PortalVisibilityBuilder.Build correctly roots at the
outdoor cell node (OutdoorCellNode) and floods into adjacent buildings through their
entrance portals. No changes to Build or OutdoorCellNode were needed.
Key finding: the task spec's building fixture used InsideSide=0 for an exit portal whose
building interior is at Y>=5 (Normal=(0,-1,0), D=5). The correct InsideSide is 1
(interior where dot<=0 -> Y>=5); with InsideSide=0 the outdoor camera (Y=-3, dot=8)
incorrectly passes as "interior" of the building so OutdoorCellNode.Build's InsideSide
flip (0->1) puts the outdoor camera on the wrong side of the gate.
Corrected fixture uses InsideSide=1 matching OutdoorCellNodeTests geometry convention
(building interior = POSITIVE dot side, outdoor = negative dot side; flip makes outdoor
negative-dot side the traversable direction). Both tests pass; full suite 214/214.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
