feat v1.32.0: polyline split, tool cursors, Esc walk-back in merge/split

- splitRoomPath in logic.ts: wall-to-wall polyline cut with interior
  vertices; validates wall crossings, self-intersection, degenerate
  parts; splitRoom delegates (2-point path); +3 unit tests (93 total)
- split UI: interior clicks add snapped intermediate points, live
  polyline + vertices + preview; new/updated toasts
- cursors: pointer for merge/delroom and split room-pick stage,
  crosshair while cutting (stage tool-* classes)
- Esc: split — drop last point, then room pick, then back to draw;
  merge — clear selection, then back to draw
- smoke_split_polyline.mjs (14 checks); TESTING/CHANGELOG same-commit

package.json

@@ -1,6 +1,6 @@
 {
   "name": "houseplan-card",
-  "version": "1.31.2",
+  "version": "1.32.0",
   "description": "Interactive house plan Lovelace card for Home Assistant",
   "license": "MIT",
   "type": "module",