feature: version one notification feature implemented.

backend/src/realtime/realtime.emitter.ts

@@ -0,0 +1,20 @@
+import { Injectable } from '@nestjs/common';
+import { Server } from 'socket.io';
+
+export function userOrgRoom(userId: string, organizationId: string): string {
+  return `user:${userId}:org:${organizationId}`;
+}
+
+@Injectable()
+export class RealtimeEmitter {
+  private server: Server | null = null;
+
+  setServer(server: Server) {
+    this.server = server;
+  }
+
+  emitToUserOrg(userId: string, organizationId: string, event: string, payload: unknown) {
+    if (!this.server) return;
+    this.server.to(userOrgRoom(userId, organizationId)).emit(event, payload);
+  }
+}

backend/src/realtime/realtime.gateway.ts

@@ -0,0 +1,81 @@
+import {
+  OnGatewayConnection,
+  OnGatewayInit,
+  WebSocketGateway,
+  WebSocketServer,
+} from '@nestjs/websockets';
+import { Logger } from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
+import { JwtService } from '@nestjs/jwt';
+import { Server, Socket } from 'socket.io';
+import { RealtimeEmitter, userOrgRoom } from './realtime.emitter';
+
+type AccessPayload = {
+  sub?: string;
+  organizationId?: string;
+  type?: string;
+};
+
+@WebSocketGateway({
+  namespace: '/realtime',
+  cors: {
+    origin: process.env.FRONTEND_URL || 'http://localhost:3001',
+    credentials: true,
+  },
+})
+export class RealtimeGateway implements OnGatewayInit, OnGatewayConnection {
+  private readonly logger = new Logger(RealtimeGateway.name);
+
+  @WebSocketServer()
+  server!: Server;
+
+  constructor(
+    private readonly jwt: JwtService,
+    private readonly config: ConfigService,
+    private readonly emitter: RealtimeEmitter,
+  ) {}
+
+  afterInit(server: Server) {
+    this.emitter.setServer(server);
+  }
+
+  async handleConnection(client: Socket) {
+    try {
+      const token = this.readAccessToken(client);
+      if (!token) {
+        client.disconnect(true);
+        return;
+      }
+
+      const payload = await this.jwt.verifyAsync<AccessPayload>(token, {
+        secret: this.config.get<string>('jwt.secret'),
+      });
+
+      if (!payload?.sub || !payload.organizationId || payload.type !== 'access') {
+        client.disconnect(true);
+        return;
+      }
+
+      const room = userOrgRoom(payload.sub, payload.organizationId);
+      await client.join(room);
+      client.data.userId = payload.sub;
+      client.data.organizationId = payload.organizationId;
+    } catch (error) {
+      this.logger.debug(`Realtime auth failed: ${String(error)}`);
+      client.disconnect(true);
+    }
+  }
+
+  private readAccessToken(client: Socket): string | null {
+    const cookieHeader = client.handshake.headers.cookie;
+    if (!cookieHeader) return null;
+    const parts = cookieHeader.split(';');
+    for (const part of parts) {
+      const [rawKey, ...rest] = part.trim().split('=');
+      if (rawKey === 'accessToken') {
+        return decodeURIComponent(rest.join('='));
+      }
+    }
+    return null;
+  }
+}

backend/src/realtime/realtime.module.ts

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+import { Module } from '@nestjs/common';
+import { JwtModule } from '@nestjs/jwt';
+import { ConfigModule, ConfigService } from '@nestjs/config';
+import { RealtimeEmitter } from './realtime.emitter';
+import { RealtimeGateway } from './realtime.gateway';
+
+@Module({
+  imports: [
+    JwtModule.registerAsync({
+      imports: [ConfigModule],
+      inject: [ConfigService],
+      useFactory: (config: ConfigService) => ({
+        secret: config.get<string>('jwt.secret'),
+      }),
+    }),
+  ],
+  providers: [RealtimeEmitter, RealtimeGateway],
+  exports: [RealtimeEmitter],
+})
+export class RealtimeModule {}