feat: implement AuthModule with authentication and RBAC features

Added AuthModule with services, controllers, and guards for authentication. Implements session management, role-based access control, 2FA, and DTOs for user login, registration, and token refresh.

backend/src/auth/rbac.service.ts

@@ -0,0 +1,42 @@
+import { Injectable } from "@nestjs/common";
+import { eq } from "drizzle-orm";
+import { DatabaseService } from "../database/database.service";
+import {
+	permissions,
+	roles,
+	rolesToPermissions,
+	usersToRoles,
+} from "../database/schemas";
+
+@Injectable()
+export class RbacService {
+	constructor(private readonly databaseService: DatabaseService) {}
+
+	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);
+	}
+
+	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)));
+	}
+}