feat v1.31.0: room cards — metrics line + proportional resize

- room label becomes a card: name on top, optional metrics below
  (temperature / humidity / avg zigbee / lights), four checkboxes in
  space settings, all off by default; lights render On/Off or '1 of 3'
- areaHum + areaLightStats pure helpers (+3 unit tests, 90 total)
- resize via corner handles in the Plan editor (hover), uniform 0.5-3x,
  scale stored as layout k next to the position; drag preserves it
- fix latent v1.25 regression: draggable HTML labels were never rendered
  in the Plan editor (static SVG only) — real name-only cards now render
  there, draggable and resizable
- repair merge/split smokes still calling removed _toggleMarkup
- validation.py: 4 label_* bools; smoke_room_cards.mjs; docs same-commit

custom_components/houseplan/validation.py

@@ -88,6 +88,10 @@ SPACE_DISPLAY_SCHEMA = vol.Schema(
         vol.Optional("temp_min"): vol.Coerce(float),
         vol.Optional("temp_max"): vol.Coerce(float),
         vol.Optional("show_lqi"): bool,
+        vol.Optional("label_temp"): bool,
+        vol.Optional("label_hum"): bool,
+        vol.Optional("label_lqi"): bool,
+        vol.Optional("label_light"): bool,
     },
     extra=vol.ALLOW_EXTRA,
 )