assistant_tool: Decouple Tool from Workspace (#26309)

This PR decouples the `Tool` trait from the `Workspace` (and from the
UI, in general).

`Tool::run` now takes a `WeakEntity<Project>` instead of a
`WeakEntity<Workspace>` and a `Window`.

Release Notes:

- N/A

crates/context_server/src/context_server_tool.rs

@@ -2,7 +2,7 @@ use std::sync::Arc;
 
 use anyhow::{anyhow, bail};
 use assistant_tool::Tool;
-use gpui::{App, Entity, Task, Window};
+use gpui::{App, Entity, Task};
 
 use crate::manager::ContextServerManager;
 use crate::types;
@@ -51,8 +51,7 @@ impl Tool for ContextServerTool {
     fn run(
         self: std::sync::Arc<Self>,
         input: serde_json::Value,
-        _workspace: gpui::WeakEntity<workspace::Workspace>,
-        _: &mut Window,
+        _project: gpui::WeakEntity<project::Project>,
         cx: &mut App,
     ) -> gpui::Task<gpui::Result<String>> {
         if let Some(server) = self.server_manager.read(cx).get_server(&self.server_id) {