fix v1.31.2: merge/split room pick highlight visible again

- .room.picked moved after .room.outlined: equal specificity, source
  order silently killed the amber highlight in markup (gotcha x4,
  documented inline)
- smoke_merge_highlight.mjs (waits out the 0.12s transition before
  reading computed colors); TESTING/CHANGELOG 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": "1.31.1"
+  "version": "1.31.2"
 }