refactor: enhance module exports and imports across services

Refactor multiple modules to improve dependency management by adding missing imports (e.g., `AuthModule`, `CryptoModule`) and ensuring essential services and repositories are exported. Update Dockerfile for better build and runtime efficiency, improve CORS handling, and enhance validation with updates to DTOs. Include package.json refinements for dependency organization.

backend/src/sessions/sessions.module.ts

@@ -7,6 +7,6 @@ import { SessionsService } from "./sessions.service";
 @Module({
 	imports: [DatabaseModule, CryptoModule],
 	providers: [SessionsService, SessionsRepository],
-	exports: [SessionsService],
+	exports: [SessionsService, SessionsRepository],
 })
 export class SessionsModule {}