- fix: Split snaps the click to the room's nearest wall instead of the grid, so
it works on non-grid-aligned rooms (imported/legacy polygons); the pull is
capped (~6 cells) so accidental mid-room clicks stay a miss; splitRoom() still
rejects a bad cut. closestPointOnBoundary() + unit test.
- docs: README (en+ru) documents Merge/Split/ruler/per-space scale (were undocumented);
TESTING.md merge/split rows + fresh self-run; new smokes smoke_merge_split,
smoke_split_nonsnap (incl. the capped-pull case).
- 73 frontend + 12 backend tests green; module eval + both cards register.
