Current Behavior

• Terminal text can only be selected by dragging the mouse
• No support for shift-click selection (holding shift and clicking to extend selection)

Proposed Feature

Add support for shift-click selection, which is a common text selection behavior in most text editors and terminals. This would allow users to:

1. Make an initial selection by clicking and dragging
2. Hold shift and click elsewhere to extend the selection to that point
3. Continue adjusting the selection by shift-clicking different points