refactor: queue primitive, tool status badges, and tool display cleanup

- Add Queue/QueueItem/QueueItemIndicator/QueueItemContent primitive
- Rewrite TodoList using Queue (clean list, no bordered cards, no priority badges)
- Add ToolStatusBadge component (Running/Completed/Error/Denied)
- Migrate CollapsibleSection from native <details> to Collapsible primitive
- Add badge prop threading through CollapsibleDisplay and CollapsibleSection
- Add status badges to OneLineDisplay and CollapsibleDisplay via ToolRenderer
- Update SubagentContainer: theme tokens + Collapsible for tool history
- Replace hardcoded gray-* colors with theme tokens throughout tool displays

src/shared/view/ui/index.ts

@@ -14,3 +14,5 @@ export { Shimmer } from './Shimmer';
 export { default as Tooltip } from './Tooltip';
 export { PromptInput, PromptInputHeader, PromptInputBody, PromptInputTextarea, PromptInputFooter, PromptInputTools, PromptInputButton, PromptInputSubmit } from './PromptInput';
 export { PillBar, Pill } from './PillBar';
+export { Queue, QueueItem, QueueItemIndicator, QueueItemContent } from './Queue';
+export type { QueueItemStatus } from './Queue';