enhancement: Add body scroll lock and top-right close button to README Badge Modal #275

In src/features/developer/components/user-profile-client.tsx, clicking 'Get README Badge' opens a modal dialog (badgeDialogOpen). When open, mouse wheel scrolling on the backdrop scrolls the underlying page. In addition, the modal only has a bottom 'Close' button without a standard top-right X close icon.

Motivation

Proper modal UX requires locking background scroll and offering an intuitive top-right dismissal button for accessibility and desktop/mobile usability.

Tasks

• When badgeDialogOpen is true, set document.body.style.overflow = "hidden" (and restore on close/unmount).
• Add an X icon button in the top-right corner of the dialog header with aria-label={t("profile.close")}.
• Ensure clicking the X button closes the dialog.

Files to Check

• src/features/developer/components/user-profile-client.tsx