Feature Request: Shift+Click to extend text selection

[ByamB4]

Feature Request

Describe the feature
Support Shift+Click to extend an existing text selection, similar to how iTerm2 and most other terminals/text editors handle it.

Current behavior
Shift+Click does not extend the current selection in Warp. The only way to make a large selection is to click and drag in one continuous motion.

Expected behavior
Users should be able to:

1. Start a selection (click or click+drag)
2. Scroll down/up
3. Shift+Click at another point to extend the selection to that position

Why is this useful?
This is a standard text selection pattern across terminals (iTerm2, Hyper, Terminal.app) and text editors. It makes selecting large blocks of output much easier without needing to drag across many lines in one motion.