- Add useCloseTabs hook to centralize tab close state with stable closeTab callback and reactive closingTabIds
- Replace killTerminalMutation/isArchivingAgent props with closingTabIds Set in split container
- Stabilize archiveAgent callback by depending on mutateAsync instead of whole mutation object
- Add bail-out to focusTabInLayout and focusPaneInLayout when already focused
- Remove redundant isArchivingAgent guard (closeTab handles dedup)
Mohamed Boudra