chore: establish learning module baseline

OpenMAIC/lib/course-framework/publish-identity.ts

@@ -0,0 +1,18 @@
+/**
+ * Stable public identity for a large-course module.
+ *
+ * The persisted classroom id is an operations-side source identifier. It must
+ * never double as the learner-facing courseware id, otherwise a manifest leaks
+ * a direct route to the mutable source classroom and bypasses its version/hash
+ * pin. Keeping this derivation deterministic also means a course re-publish
+ * creates the next immutable version of the same public module.
+ */
+export function courseModuleCoursewareId(courseId: string, moduleIndex: number): string {
+  if (!/^[a-zA-Z0-9_-]+$/.test(courseId)) {
+    throw new Error(`Invalid course id: ${courseId}`);
+  }
+  if (!Number.isInteger(moduleIndex) || moduleIndex < 1) {
+    throw new Error(`Invalid module index: ${moduleIndex}`);
+  }
+  return `course_${courseId}_module_${moduleIndex}`;
+}