fix(ui): fix useRowWipe stuck blur and useCollapsible race conditions

- Remove anim.stop() from useRowWipe cleanup — stopping mid-animation
  leaves WAAPI fill-forward that overrides cleared inline styles. Let
  animations run to completion; cancelAnimationFrame prevents starts.
- Add generation counter to useCollapsible to guard against stale
  microtask and promise callbacks on rapid open/close toggling.
- Use .then(ok, err) instead of .catch().then() to prevent callbacks
  firing after animation cancellation.
- Remove redundant fade constant in ShellExpanded.
- Clean up unused imports in context-tool-results.tsx.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>