feat v1.28.0: sub-area rooms — manual device placement without an HA area (issue #3)

- area-less rooms appear in the marker room list ('no area, manual'); markers
  store room_id and land at the room centre; dialog reopen restores the choice
- pure parseRoomRef (space#area / space#@roomId) + unit tests; backend schema
- ROADMAP phase 11 closed; TESTING.md row; smoke_subarea.mjs

src/i18n/ru.json

@@ -243,5 +243,6 @@
   "mode.view": "Просмотр",
   "mode.plan": "План",
   "mode.devices": "Устройства",
-  "display.value": "Значение вместо иконки"
+  "display.value": "Значение вместо иконки",
+  "marker.subarea": "без зоны, вручную"
 }