feat(backend): implement pricing engine for loyalty points and 3-level promotions

apps/backend/src/index.ts

@@ -19,6 +19,7 @@ import { lazadaOrderRoute } from "./routes/lazadaOrder";
 import { customersRoute } from "./routes/customers";
 import { couponsRoute } from "./routes/coupons";
 import { reviewsRoute } from "./routes/reviews";
+import { promotionsRoute } from "./routes/promotions";
 const PORT = process.env.PORT ? parseInt(process.env.PORT) : 3000;
 const CORS_ORIGIN = process.env.CORS_ORIGIN || "http://localhost:5173";
 const JWT_SECRET = process.env.JWT_SECRET || "homaroma_secret_2026_scent";
@@ -82,7 +83,7 @@ const app = new Elysia()
     return file;
   })
   .group("/api", (app) =>
-    app.use(authRoute).use(categoriesRoute).use(productsRoute).use(uploadRoute).use(heroRoute).use(ordersRoute).use(settingsRoute).use(articlesRoute).use(tiktokRoute).use(rawMaterialsRoute).use(shopeeRoute).use(tiktokOrderRoute).use(lazadaOrderRoute).use(customersRoute).use(couponsRoute).use(reviewsRoute)
+    app.use(authRoute).use(categoriesRoute).use(productsRoute).use(uploadRoute).use(heroRoute).use(ordersRoute).use(settingsRoute).use(articlesRoute).use(tiktokRoute).use(rawMaterialsRoute).use(shopeeRoute).use(tiktokOrderRoute).use(lazadaOrderRoute).use(customersRoute).use(couponsRoute).use(reviewsRoute).use(promotionsRoute)
   )
   .listen(PORT);