Pass up intent with completion requests (#31710)

This PR adds a new `intent` field to completion requests to assist in
categorizing them correctly.

Release Notes:

- N/A

---------

Co-authored-by: Ben Brandt <benjamin.j.brandt@gmail.com>

crates/git_ui/Cargo.toml

@@ -59,6 +59,7 @@ util.workspace = true
 workspace-hack.workspace = true
 workspace.workspace = true
 zed_actions.workspace = true
+zed_llm_client.workspace = true
 
 [target.'cfg(windows)'.dependencies]
 windows.workspace = true