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/ui/error-banner.module.css

@@ -0,0 +1,42 @@
+.banner {
+  display: flex;
+  align-items: flex-start;
+  gap: var(--space-3);
+  padding: var(--space-3) var(--space-4);
+  background-color: var(--color-danger-50);
+  border: 1px solid var(--color-danger-100);
+  border-radius: var(--radius-md);
+  color: var(--color-danger-700);
+  font-size: var(--font-size-sm);
+  line-height: var(--line-height-normal);
+}
+
+.icon {
+  flex-shrink: 0;
+  margin-top: 1px;
+  font-size: var(--font-size-md);
+}
+
+.message {
+  flex: 1;
+}
+
+.dismiss {
+  flex-shrink: 0;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  width: 24px;
+  height: 24px;
+  border: none;
+  border-radius: var(--radius-sm);
+  background: transparent;
+  color: var(--color-danger-600);
+  font-size: var(--font-size-sm);
+  cursor: pointer;
+  transition: background-color var(--transition-fast);
+}
+
+.dismiss:hover {
+  background-color: var(--color-danger-100);
+}