Task 6 (dat-reader bridge) obsoleted: WB ships DefaultDatReaderWriter
which takes a dat-directory path and constructs all four databases
(Portal/HighRes/Language + CellRegions) internally. We can use it
directly instead of bridging our DatCollection. Adjustment 1 noted
in the plan; full bring-up deferred to Task 9.
Task 7: GameWindow constructs WbMeshAdapter when
ACDREAM_USE_WB_FOUNDATION=1 is set; pairs with Dispose. Field is
null when flag is off, so no behavioral effect on default-off path.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>