Rename all --color-gh-* CSS tokens to --color-*, update Tailwind class names (bg-gh-*, text-gh-*, border-gh-*, etc.) across all TSX/TS files, rename GhButton component and file to Button, and remove trivial descriptive comments.
Apply GH-dark design tokens to Modal container, CreateServerModal, and DeleteServerModal: overlay/canvas card pattern, form-input class, GhButton variants (primary, ghost, danger-solid), and GH token text/border colors.
