Component spacing and contrast

Refined Badge spacing, corrected Divider colors, and new semantic tokens for foreground contrast.

Improved

Added foreground contrast tokens and applied the primary contrast role to selected controls. Added selection color tokens so native selection states can use the same theme contract. TextArea is now exported from the package entry point, completing the field family available to consumers.

Fixed

Divider now uses its dedicated border token, allowing its visual weight to be changed without affecting other borders. Badge padding correctly accounts for icons and close controls, and icon-only badges no longer accept a close control that cannot be represented accessibly.

Corrected TextField edge padding and Switch knob styling. Theme generation now preserves CSS when a color mode has no tokens.