fix: address DataTable, Modal, and ErrorBoundary review feedback

[Copilot]

Addresses 9 review comments from the component library PR: type safety gaps, duplicate ESC handling, duplicate aria-labelledby IDs, missing imports, and pagination state drift.

DataTable

• key: keyof T & string — was string, allowing keys that don't exist on T; render value param, sortKey state, and handleSort updated accordingly
• Remove role="grid" — native <table> semantics are correct; grid implies unimplemented arrow-key navigation
• Page clamping — useEffect resets page to 0..totalPages-1 when data.length/pageSize changes, preventing stuck empty views
• ReactNode import — was referencing React.ReactNode without importing React

// Before
key: string;
render?: (value: unknown, row: T) => React.ReactNode;

// After
key: keyof T & string;
render?: (value: T[keyof T & string], row: T) => ReactNode;

Modal

• Remove onKeyDown ESC handler — ESC was handled by both onKeyDown and the native cancel event, potentially calling onClose twice; now relies solely on the cancel listener
• useId() for title id — hard-coded "modal-title" caused duplicate IDs with multiple Modal instances; replaced with useId() so aria-labelledby and <h2 id> are always paired and unique
• type MouseEvent import — was using React.MouseEvent without importing React

ErrorBoundary test

• Added beforeEach/afterEach to vitest imports — were used but not imported, causing test suite failure at runtime

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