Frontend: Optimize chessboard rendering for mobile devices

[chinweobtagaz]

Description

Mobile users are reporting high battery drain and slight lag when playing bullet chess on older devices.

What Needs to be Done

• Profile the ChessboardComponent using React DevTools.
• Memoize heavy sub-components (like individual squares and pieces) to prevent unnecessary re-renders.
• Optimize the drag-and-drop library integration for touch screens.
• Limit WebWorker engine depth on mobile by default to save CPU cycles.

Acceptance Criteria

• React re-renders are isolated only to the squares that change during a move.
• Touch-and-drag latency is reduced to under 30ms on average devices.
• Lighthouse performance score on mobile improves by at least 15 points.
• Battery consumption significantly reduced during active play.