Created an Intuitive GUI

[Kr-Adarsh]

Enhanced the Student Management System GUI to improve usability and intuitiveness:

1. Navigation: Improved button connectivity for seamless transitions between pages, allowing smooth navigation between adding, updating, and checking student records.
2. Input Validation: Added validation for roll numbers and percentages, ensuring only valid data is entered. Status bar messages provide instant feedback on user actions.
3. Progress Bar: Integrated a progress bar to give visual feedback when records are added.
4. Table Display: Optimized the student records table for readability with dynamic row adjustments and clear headers.
5. Keyboard Accessibility: Enabled Enter key functionality for smooth input navigation and form submission.
6. Record Management: Added/updated student records with feedback for successful operations or errors.
7. Stylesheet Support: Included external QSS stylesheet for easy customization.

These improvements make the GUI more intuitive, responsive, and accessible. Please do mention if there's anything to add or improve.