feat: add modular services and repositories for improved code organization

Introduce repository pattern across multiple services, including `favorites`, `tags`, `sessions`, `reports`, `auth`, and more. Decouple crypto functionalities into modular services like `HashingService`, `JwtService`, and `EncryptionService`. Improve testability and maintainability by simplifying dependencies and consolidating utility logic.

backend/src/s3/s3.service.ts

@@ -1,9 +1,10 @@
 import { Injectable, Logger, OnModuleInit } from "@nestjs/common";
 import { ConfigService } from "@nestjs/config";
 import * as Minio from "minio";
+import type { IStorageService } from "../common/interfaces/storage.interface";
 
 @Injectable()
-export class S3Service implements OnModuleInit {
+export class S3Service implements OnModuleInit, IStorageService {
 	private readonly logger = new Logger(S3Service.name);
 	private minioClient: Minio.Client;
 	private readonly bucketName: string;