[improvement] rename packages dir to src (#3659)

src/coupon/shared.ts

@@ -0,0 +1,14 @@
+export type Coupon = {
+  id: string;
+  name: string;
+  endAt: number;
+  value: number;
+  startAt: number;
+  reason?: string;
+  discount?: number;
+  unitDesc?: string;
+  condition?: string;
+  valueDesc?: string;
+  description: string;
+  denominations?: number;
+};