feat(react): replace react-transition-group with custom useTransition hook

[wangdicoder]

Summary

• Replace react-transition-group dependency with a lightweight custom useTransition hook and updated Transition component
• The hook implements a CSS class-toggling state machine (enter → entering → entered → exit → exiting → exited) using requestAnimationFrame and transitionend events
• Zero SCSS changes required — all existing animation classes (-enter, -enter-active, -enter-done, -exit, -exit-active, -exit-done) are preserved
• Migrated all direct CSSTransition consumers (Overlay, Modal, Drawer, Message) to use the Transition component
• Replaced TransitionGroup usage in the new Waterfall component with manual exiting-item tracking
• Removes unmaintained dependency and prepares for React 19 compatibility (findDOMNode removal)

Release

• Bump: minor
• Affected packages: @tiny-design/react (fixed version group includes @tiny-design/tokens and @tiny-design/icons)

Test plan

• All 91 test suites pass (535 tests)
• Build succeeds with no react-transition-group references in output
• Manually verify animations in docs site:
  • Popup/Tooltip/Dropdown: zoom animations on hover/click
  • Modal: slide/scale open and close animations
  • Drawer: slide from each direction (open and close)
  • Message: fade-slide toast appearance and dismissal
  • Alert: close animation
  • Form: error message slide-down
  • Waterfall: item exit fade animation
  • Collapse/Tree/Menu: expand/collapse (unchanged, sanity check)

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