ux(connections): the connection tree loses its expanded state and selection when a connection is added #1821

Problem

In a debug build (dev at 25c766c): expand Local MySQL → Databases → querya → Tables, open a table, then add a second connection (Ctrl+N, Mongo, Save). When the dialog closes, the tree is rebuilt: the selected row changes (the new connection is highlighted, the MySQL one was the active workspace) and the expanded branches collapse back to the database level.

Expected

Adding a connection only inserts a row; the other rows keep their expansion and the active selection stays on the connection the workspace shows.

Where

ConnectionsPanelState.reloadConnectionsFromDb / _loadData (called after MainScreenDialogs._showNewConnection): keep the expanded-node and selection state across the reload.