The 2D affordance dispatcher (`startAffordanceDrag`) now begins the matching
reshaping interaction scope (boundary / hole / curve / endpoint) on pointer-down
and tears it down on release/cancel, matched by node id. This makes the
contextual snapping HUD show the right chip during polygon vertex/edge and wall
endpoint/curve edits, and lets `getActiveSnapContext()` resolve the correct
per-context snapping mode the affordance snap math already reads.
Wall creation is owned by the 3D `WallTool`, which is dead in 2D-only view
(canvas `display:none`). Mirror the slab/ceiling 2D-only committers: commit
locally via `createWallOnCurrentLevel`, gated on `viewMode === '2d'`, chaining
the next segment from the committed wall's resolved end. Split/3D keep their
single-owner tool commit.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
