feat: Add loot builder backend + static data + DB migration

- Migration 013: loot_profiles table (JSONB loot_table + loot_groups, license-scoped)
- TypeORM entity matching migration schema exactly
- NestJS loot module: 10 endpoints (CRUD, duplicate, apply, import, export, containers)
- Multiplier logic recursively scales Min/Max/Scrap across loot tables and groups
- Apply-to-server writes BetterLoot JSON via NATS file manager + RCON reload
- Frontend static data: 191 Rust items, 51 container prefabs
- TypeScript types for BetterLoot data model (PrefabLoot, LootEntry, LootRNG, etc.)
- Fix vue-tsc errors: UngroupedItems uses LootRNG, null safety in store/view

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend-nest/src/modules/loot/dto/update-loot-profile.dto.ts

@@ -0,0 +1,30 @@
+import { IsString, IsOptional, IsObject, IsBoolean, MaxLength } from 'class-validator';
+import { ApiPropertyOptional } from '@nestjs/swagger';
+
+export class UpdateLootProfileDto {
+  @ApiPropertyOptional()
+  @IsString()
+  @MaxLength(100)
+  @IsOptional()
+  profile_name?: string;
+
+  @ApiPropertyOptional()
+  @IsString()
+  @IsOptional()
+  description?: string;
+
+  @ApiPropertyOptional()
+  @IsObject()
+  @IsOptional()
+  loot_table?: Record<string, any>;
+
+  @ApiPropertyOptional()
+  @IsObject()
+  @IsOptional()
+  loot_groups?: Record<string, any>;
+
+  @ApiPropertyOptional()
+  @IsBoolean()
+  @IsOptional()
+  is_active?: boolean;
+}