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/UserDto.ts

@@ -0,0 +1,29 @@
+export interface CreateUserDto {
+  username: string;
+  email: string;
+}
+
+export interface UpdateUserDto {
+  id: string;
+  username?: string;
+  email?: string;
+}
+
+export interface ShortUserDto {
+  id: string;
+  username: string;
+  state: number;
+  authLevel: 0 | 1;
+}
+
+export interface DetailUserDto {
+  id: string;
+  orgid: string | null;
+  username: string;
+  email: string;
+  fname: string;
+  lname: string;
+  code: string | null;
+  phone: string | null;
+  state: number;
+}