feat v1.37.0: open boundaries (virtual walls)

- room.open_to symmetric links; 'Open boundary' plan tool toggles the
  shared wall pair under the click (sharedBoundary collinear-overlap
  math + distToSegment pull, same as Split); dashed rendering with an
  amber hot state while the tool is active; Esc -> Draw
- glow: the clip becomes the transitive open zone (openZoneOf BFS,
  either-direction links) + door sectors from the zone's outer walls
- model rooms carry open_to; backend ROOM_SCHEMA open_to: [str]
- +3 unit tests (104), smoke_openwall.mjs (8 checks); docs same-commit

custom_components/houseplan/manifest.json

@@ -16,5 +16,5 @@
   "issue_tracker": "https://github.com/Matysh/houseplan-card/issues",
   "requirements": [],
   "single_config_entry": true,
-  "version": "1.36.4"
+  "version": "1.37.0"
 }