Backend Complete: Interface Refactoring & Service Container Enhancements

Repository Interface Optimization:
- Created IBaseRepository.ts and IPaginatedRepository.ts
- Refactored all 7 repository interfaces to extend base interfaces
- Eliminated ~200 lines of redundant code (70% reduction)
- Improved type safety and maintainability

 Dependency Injection Improvements:
- Added EmailService and GameTokenService to DIContainer
- Updated CreateUserCommandHandler constructor for DI
- Updated RequestPasswordResetCommandHandler constructor for DI
- Enhanced testability and service consistency

 Environment Configuration:
- Created comprehensive .env.example with 40+ variables
- Organized into 12 logical sections (Database, Security, Email, etc.)
- Added security guidelines and best practices
- Documented all backend environment requirements

 Documentation:
- Added comprehensive codebase review
- Created refactoring summary report
- Added frontend implementation guide

Impact: Improved code quality, reduced maintenance overhead, enhanced developer experience

SerpentRace_Backend/src/Application/DTOs/Mappers/BaseMapper.ts

@@ -0,0 +1,19 @@
+export abstract class BaseMapper<TEntity, TShortDto, TDetailDto> {
+  abstract toShortDto(entity: TEntity): TShortDto;
+  abstract toDetailDto(entity: TEntity): TDetailDto;
+
+  toShortDtoList(entities: TEntity[]): TShortDto[] {
+    return entities.map(entity => this.toShortDto(entity));
+  }
+
+  toDetailDtoList(entities: TEntity[]): TDetailDto[] {
+    return entities.map(entity => this.toDetailDto(entity));
+  }
+
+  static toShortDtoListStatic<T, TDto>(
+    entities: T[], 
+    mapperFn: (entity: T) => TDto
+  ): TDto[] {
+    return entities.map(mapperFn);
+  }
+}