feat: complete house plan maker application

Full-featured house/apartment floor plan editor with:

- Turborepo monorepo (React/Vite client, Fastify/Prisma server, shared Zod schemas)
- 2D room editor with walls, doors, windows, furniture, electrical elements
- 3D room preview with Three.js (auto-hide nearest walls, bird's eye default)
- Wall projection views with interactive drag (elevation, position)
- Apartment floor plan view with room positioning
- Copy/paste, alignment tools, measurement tool, annotations
- Item-attached annotations with leader lines (visible on projections)
- Door open direction (LEFT/RIGHT/INWARD/OUTWARD) with swing arc
- Floor type textures (wood, tile, concrete, laminate, herringbone)
- Wall color picker for 3D view
- Furniture: bed, desk, wardrobe, sofa, table, chair, shelf, nightstand, dresser, bookcase, TV (with stand toggle), AC unit
- Furniture elevation support (wall-mounted items)
- Auto-save with dirty state tracking, batch save API
- Rotation-aware collision detection (SAT/OBB) with 3D elevation check
- Rotation-aware hit testing
- i18n (English/Russian) with locale-aware number formatting
- Dark mode with system preference detection
- Undo/redo, keyboard shortcuts, scale bar
- PDF/PNG/JSON export and JSON import
- Focus trap modal, toast notifications, tooltips
- Responsive layout with overlay palettes

apps/client/src/components/editor/symbols/electrical/CeilingLightSymbol.tsx

@@ -0,0 +1,23 @@
+import { Group, Circle, Line } from 'react-konva';
+
+interface CeilingLightSymbolProps {
+  readonly x: number;
+  readonly y: number;
+  readonly rotation: number;
+  readonly color: string;
+  readonly scale: number;
+}
+
+/** IEC ceiling light: circle with cross pattern inside. */
+export function CeilingLightSymbol({ x, y, rotation, color, scale }: CeilingLightSymbolProps) {
+  const r = 10 * scale;
+
+  return (
+    <Group x={x} y={y} rotation={rotation}>
+      <Circle radius={r} stroke={color} strokeWidth={1.5} fill="transparent" listening={false} />
+      {/* Cross pattern */}
+      <Line points={[-r, 0, r, 0]} stroke={color} strokeWidth={1.2} listening={false} />
+      <Line points={[0, -r, 0, r]} stroke={color} strokeWidth={1.2} listening={false} />
+    </Group>
+  );
+}