feat: implement messaging functionality with real-time updates

- Introduced a messaging module on the backend using NestJS, including repository, service, controller, DTOs, and WebSocket Gateway.
- Developed a frontend messaging page with conversation management, real-time message handling, and chat UI.
- Implemented `MessageService` for API integrations and `SocketProvider` for real-time WebSocket updates.
- Enhanced database schema to support conversations, participants, and messages with Drizzle ORM.

backend/src/messages/dto/create-message.dto.ts

@@ -0,0 +1,11 @@
+import { IsNotEmpty, IsString, IsUUID, MaxLength } from "class-validator";
+
+export class CreateMessageDto {
+	@IsUUID()
+	recipientId!: string;
+
+	@IsString()
+	@IsNotEmpty()
+	@MaxLength(2000)
+	text!: string;
+}