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/auth/rbac.service.ts

@@ -1,42 +1,15 @@
 import { Injectable } from "@nestjs/common";
-import { eq } from "drizzle-orm";
-import { DatabaseService } from "../database/database.service";
-import {
-	permissions,
-	roles,
-	rolesToPermissions,
-	usersToRoles,
-} from "../database/schemas";
+import { RbacRepository } from "./repositories/rbac.repository";
 
 @Injectable()
 export class RbacService {
-	constructor(private readonly databaseService: DatabaseService) {}
+	constructor(private readonly rbacRepository: RbacRepository) {}
 
 	async getUserRoles(userId: string) {
-		const result = await this.databaseService.db
-			.select({
-				slug: roles.slug,
-			})
-			.from(usersToRoles)
-			.innerJoin(roles, eq(usersToRoles.roleId, roles.id))
-			.where(eq(usersToRoles.userId, userId));
-
-		return result.map((r) => r.slug);
+		return this.rbacRepository.findRolesByUserId(userId);
 	}
 
 	async getUserPermissions(userId: string) {
-		const result = await this.databaseService.db
-			.select({
-				slug: permissions.slug,
-			})
-			.from(usersToRoles)
-			.innerJoin(
-				rolesToPermissions,
-				eq(usersToRoles.roleId, rolesToPermissions.roleId),
-			)
-			.innerJoin(permissions, eq(rolesToPermissions.permissionId, permissions.id))
-			.where(eq(usersToRoles.userId, userId));
-
-		return Array.from(new Set(result.map((p) => p.slug)));
+		return this.rbacRepository.findPermissionsByUserId(userId);
 	}
 }