feat: implement course listing and retrieval API with dedicated controller, service, and types.

Backend/src/types/courses.types.ts

@@ -0,0 +1,26 @@
+import { Course, Prisma } from '@prisma/client';
+
+// Use Prisma's CourseCreateInput for creating courses
+export interface createCourse {
+    data: Prisma.CourseCreateInput;
+}
+
+// Response type uses Prisma's Course model
+export interface createCourseResponse {
+    code: number;
+    message: string;
+    data: Course;
+}
+
+export interface listCourseResponse {
+    code: number;
+    message: string;
+    data: Course[];
+    total: number | null;
+}
+
+export interface getCourseResponse {
+    code: number;
+    message: string;
+    data: Course | null;
+}