Component spacing and contrast

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

New features

• Added foreground contrast tokens and selection color tokens.
• Exported TextArea from the package entry point.

Improvements

• Applied the primary contrast role to selected controls.
• Added a press stretch animation to the Switch knob. It is skipped while the switch is disabled.

Bug fixes

• Fixed Divider to use its dedicated border token.
• Fixed Badge padding with icons and close controls. Icon-only badges no longer accept a close control.
• Fixed TextField edge padding and Switch knob styling.
• Fixed theme generation dropping CSS when a color mode has no tokens.