Show unavailable providers as coming-soon placeholders

- Keep Claude Code and Cursor in provider list as disabled options
- Remove unused Claude agent SDK dependency from server
- Delete stale plan-mode deep-dive doc
e9655d43d5Julius Marminge committed on 3/6/2026, 7:00:41 AM· committed by Julius Marmingeparentf0a7dda
5 files changedLine totals unavailable