enhancement: Add 1-click Clear button (X) inside SearchField #265

In src/features/leaderboard/components/search-field.tsx, users can filter developers or countries by typing into the search input. While keyboard users can press Escape to clear, mouse and touch users must manually backspace all characters.

Motivation

A clear button (X) is standard search input UX on desktop and mobile, enabling fast filter reset.

Tasks

• When value.trim().length > 0, render an icon button with X (from lucide-react) positioned at end-2.5.
• Clicking the button calls onChange("") and retains focus on the input.
• Ensure the shortcut badge / is hidden when the clear button is shown to avoid visual overlap.
• Provide an accessible aria-label for screen readers.

Files to Check

• src/features/leaderboard/components/search-field.tsx
• src/locales/en.json & src/locales/ar.json