feat(backend): sessions routes

packages/backend/src/app.ts

@@ -4,6 +4,7 @@ import type { Db } from './db/client.js';
 import { ApiError } from './lib/errors.js';
 import { cardsRouter } from './routes/cards.js';
 import { lessonsRouter } from './routes/lessons.js';
+import { sessionsRouter } from './routes/sessions.js';
 
 export function createApp(db: Db): Express {
   const app = express();
@@ -12,6 +13,7 @@ export function createApp(db: Db): Express {
   app.get('/api/health', (_req, res) => res.json({ ok: true }));
   app.use('/api/lessons', lessonsRouter(db));
   app.use('/api', cardsRouter(db));
+  app.use('/api/sessions', sessionsRouter(db));
 
   app.use((err: unknown, _req: Request, res: Response, _next: NextFunction) => {
     if (err instanceof ZodError) {