- Track chat input height via ResizeObserver and chatInputStateStore; ignore outside-click collapse when interacting with scroll-to-latest bar.

- Simplify and restyle tool cards (task, terminal, file op, mermaid, todo, create plan) and related SCSS.

- Adjust Markdown, planner button, subagent/user message styles, VirtualMessageList, ModelRoundItem, ScrollToLatestBar, and ThemeManager for consistency.