feat(copy-button): Copy Button with Tooltip and icon transition fixes

[gab-az]

Summary

• Adds CopyButton and Tooltip components with specs (.specs/copy-button.md, .specs/tooltip.md), Storybook stories, and package exports.
• CopyButton wraps IconButton in Tooltip for hover/focus labels and post-copy feedback; default kind is outlined; copy/check icon swap uses iconTransition.
• IconButton icon-transition preset uses a fixed-size host so glyph swaps do not resize the control; outlined border uses --border-default.
• Tooltip popup motion via popup-scale-transition preset aligned with animate.js; text-contrast theme token for contrast surface text.

Test plan

• Storybook: Actions / Copy Button — hover/focus tooltip, click copies and shows copied state + tooltip, icon transition without layout shift
• Storybook: Overlay / Tooltip — placements, open/close motion, keyboard dismiss
• Verify outlined CopyButton default in docs/controls
• pnpm lint/type-check on webkit package if CI does not cover locally