feat: add WALL_CABLE electrical type and room outlet/switch count stats

Add wall cable item — a bare cable exit from the wall for direct
consumer connection without an outlet. Includes 2D symbol (circle +
cable stub), 3D mesh (round plate + protruding cable), and palette entry.

Also add outlet and switch count metrics to the room info section in
the properties panel.

apps/client/public/locales/en/translation.json

@@ -242,6 +242,8 @@
   "properties.curtainLeftOpen": "Left open",
   "properties.curtainRightOpen": "Right open",
   "properties.curtainFabricColor": "Fabric color",
+  "properties.outletCountStat": "Outlets",
+  "properties.switchCountStat": "Switches",
   "properties.outletWidth": "Outlet width",
   "properties.outletHeight": "Outlet height",
   "properties.outletCount": "Count",
@@ -293,6 +295,7 @@
   "electrical.junction": "Junction",
   "electrical.lights": "Lights",
   "electrical.cable": "Cable",
+  "electrical.wallCable": "Wall Cable",
 
   "furniture.title": "Furniture",
   "furniture.searchPlaceholder": "Search furniture\u2026",

apps/client/public/locales/ru/translation.json

@@ -245,6 +245,8 @@
   "properties.curtainLeftOpen": "Левая створка",
   "properties.curtainRightOpen": "Правая створка",
   "properties.curtainFabricColor": "Цвет ткани",
+  "properties.outletCountStat": "Розетки",
+  "properties.switchCountStat": "Выключатели",
   "properties.outletWidth": "Ширина розетки",
   "properties.outletHeight": "Высота розетки",
   "properties.outletCount": "Количество",
@@ -296,6 +298,7 @@
   "electrical.junction": "Распределительная коробка",
   "electrical.lights": "Освещение",
   "electrical.cable": "Кабель",
+  "electrical.wallCable": "Кабель из стены",
 
   "furniture.title": "Мебель",
   "furniture.searchPlaceholder": "Поиск мебели\u2026",