Migrate "Master Schedule" (Timetable)

[Ryan2486]

Create a complex ScheduleService to fetch global data.

• 1. Implement the main Grid View (Calendar style).
• 2. Integrate Drag & Drop functionality (using @angular/cdk/drag-drop).
• 3. Logic: Implement visual alerts for conflicts (e.g., Room already occupied at this time).
• 4. Filters: Add ability to view schedule by Class, by Teacher, or by Room.