getSyllabus abstract method
Fetches the detailed syllabus for a course offering.
Returns syllabus information including course objectives, textbooks,
grading policy, and weekly plan, or null when the authoring teacher
hasn't submitted one yet (the page shows 尚未登錄).
The courseNumber should be a course offering number (e.g., "346774"),
and teacherId is the authoring teacher's ID (one of the teachers IDs
of a ScheduleDto).
Throws an Exception if the syllabus tables are not found.
Implementation
Future<SyllabusDto?> getSyllabus({
required String courseNumber,
required String teacherId,
});