feat(schedule): add academic system sync and course management improvements

- add educational system synchronization with username/password authentication
- implement long-press course deletion with single/all options
- add multi-lane course display for overlapping same-name courses
- refactor course detail screen with ScrollView and improved layout
- fix teacher display to show per-time-slot instructors instead of single field
- add settings modal with sync option and loading states

src/services/scheduleService.ts

@@ -32,6 +32,19 @@ interface CreateScheduleCourseResponse {
   course: ScheduleCourseDTO;
 }
 
+interface SyncScheduleRequest {
+  username: string;
+  password: string;
+  semester?: string;
+}
+
+interface SyncScheduleResponse {
+  success: boolean;
+  message: string;
+  synced_count: number;
+  error_message?: string;
+}
+
 const toCourse = (dto: ScheduleCourseDTO): Course => ({
   id: dto.id,
   name: dto.name,
@@ -64,7 +77,12 @@ class ScheduleService {
   async deleteCourse(courseId: string): Promise<void> {
     await api.delete(`/schedule/courses/${courseId}`);
   }
+
+  async syncSchedule(req: SyncScheduleRequest): Promise<SyncScheduleResponse> {
+    const response = await api.post<SyncScheduleResponse>('/schedule/sync', req);
+    return response.data;
+  }
 }
 
 export const scheduleService = new ScheduleService();
-export type { CreateScheduleCourseRequest };
+export type { CreateScheduleCourseRequest, SyncScheduleRequest };