feat: add outlet direction (horizontal/vertical), wall light styles, floor textures, and stretch ceiling

- Add configurable outlet direction (horizontal/vertical) stored in metadata
- Add wall light style variants (classic, pendant-globe, sconce-up, sconce-down)
- Add PBR floor textures including natural oak
- Add stretch ceiling offset support with DB migration
- Add furniture surface texture selection
- Add canvas theme colors utility for dark mode support
- Update projection views with improved rendering
- Add EN and RU translations for all new properties

apps/server/prisma/migrations/20260408040000_add_room_stretch_ceiling_offset/migration.sql

@@ -0,0 +1,3 @@
+-- Distance (meters) the stretch ceiling hangs below the structural ceiling.
+-- 0 = no stretch ceiling. Applied per room and used purely for visualization.
+ALTER TABLE "Room" ADD COLUMN "stretchCeilingOffset" REAL NOT NULL DEFAULT 0;