feat: add subscription middleware

Made-with: Cursor

src/app.ts

@@ -5,6 +5,7 @@ import redisPlugin from './plugins/redis.js';
 import securityPlugin from './plugins/security.js';
 import rateLimitPlugin from './plugins/rateLimit.js';
 import authPlugin from './plugins/auth.js';
+import subscriptionPlugin from './plugins/subscription.js';
 import { authRoutes } from './routes/auth.js';
 import { env } from './config/env.js';
 import { randomUUID } from 'node:crypto';
@@ -72,6 +73,7 @@ export async function buildApp(): Promise<FastifyInstance> {
   await app.register(securityPlugin);
   await app.register(rateLimitPlugin);
   await app.register(authPlugin);
+  await app.register(subscriptionPlugin);
   await app.register(authRoutes, { prefix: '/auth' });
 
   app.get('/health', async () => ({ status: 'ok', timestamp: new Date().toISOString() }));