Photopea - Full Width Work Area & Clean UI

Removes the right-side ad bar, expands the main work area to full width, fixes cursor/tool coordinate misalignment caused by sidebar removal (via getBoundingClientRect interception), removes the file-format footer image, hides the About/Learn/Blog/API info buttons, hides the Account button from the topbar, centers homepage content vertically and horizontally without causing a scrollbar, and removes Install Photopea and Generate with AI buttons.