- connection store: connectedIds array, per-connection health/serverInfo maps
- connect() no longer disconnects existing connections
- New switchTo(id), disconnectById(id), isConnectedById(id) methods
- Per-connection health check timers (Map-based)
- ConnectionCard: switch to connected, connect if not, disconnect if active
- MainArea: per-connection tab state (save/restore on switch)
- Connection switcher dropdown in tab bar showing all open connections
- Clean up tab state when connection disconnects