test:add test cases for MediaDetailModal components

Add unit test cases for the MediaDetailModal.tsx and MediaGridItem.tsx components to improve test coverage using Vitest and React Testing Library. Create separate test files inside the test/ folder without modifying any existing source files. The tests should cover component rendering, correct display of props (such as title, image, and description), conditional rendering (like modal open/close behavior), user interactions (click events, closing actions), and edge cases (empty or missing props). Ensure the tests are clean, readable, and do not affect existing functionality.