Make `assistant::QuoteSelection` shortcuts work in agent threads (#32270)

Closes: https://github.com/zed-industries/zed/discussions/30626

Release Notes:

- Fixed `assistant::QuoteSelection` default shortcuts (`cmd->` and
`ctrl->`) so they work in Agent threads too (in addition to text threads
and in the Editor pane).
6d95fd9167Peter Tripp committed on 6/6/2025, 9:50:55 PM· committed by GitHubparent899153d
2 files changedLine totals unavailable