agent: Render diffs for the edit file tool (#29234)

This PR implements the `ToolCard` for the edit file tool, which allow us
to display an editor with a diff in the thread view with the changes
performed by the model.

- [x] Fix buffer sometimes displaying empty
- [x] Stop buffer from scrolling together with the thread
- [x] Fix multibuffer header sometimes appearing
- [x] Fix buffer height issue
- [x] Implement "full height" expand button
- [x] Add "Jump To File" functionality
- [x] Polish and refine styles

Release Notes:

- agent: Added diff preview cards in the thread view for edits performed
by the agent.

---------

Co-authored-by: João Marcos <marcospb19@hotmail.com>
Co-authored-by: Richard Feldman <oss@rtfeldman.com>
Co-authored-by: Agus Zubiaga <hi@aguz.me>
Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>

crates/assistant_tool/Cargo.toml

@@ -28,6 +28,7 @@ serde.workspace = true
 serde_json.workspace = true
 text.workspace = true
 util.workspace = true
+workspace.workspace = true
 workspace-hack.workspace = true
 
 [dev-dependencies]

crates/assistant_tool/src/assistant_tool.rs

@@ -10,14 +10,16 @@ use std::sync::Arc;
 
 use anyhow::Result;
 use gpui::AnyElement;
+use gpui::AnyWindowHandle;
 use gpui::Context;
 use gpui::IntoElement;
 use gpui::Window;
-use gpui::{App, Entity, SharedString, Task};
+use gpui::{App, Entity, SharedString, Task, WeakEntity};
 use icons::IconName;
 use language_model::LanguageModelRequestMessage;
 use language_model::LanguageModelToolSchemaFormat;
 use project::Project;
+use workspace::Workspace;
 
 pub use crate::action_log::*;
 pub use crate::tool_registry::*;
@@ -65,6 +67,7 @@ pub trait ToolCard: 'static + Sized {
         &mut self,
         status: &ToolUseStatus,
         window: &mut Window,
+        workspace: WeakEntity<Workspace>,
         cx: &mut Context<Self>,
     ) -> impl IntoElement;
 }
@@ -76,6 +79,7 @@ pub struct AnyToolCard {
         entity: gpui::AnyEntity,
         status: &ToolUseStatus,
         window: &mut Window,
+        workspace: WeakEntity<Workspace>,
         cx: &mut App,
     ) -> AnyElement,
 }
@@ -86,11 +90,14 @@ impl<T: ToolCard> From<Entity<T>> for AnyToolCard {
             entity: gpui::AnyEntity,
             status: &ToolUseStatus,
             window: &mut Window,
+            workspace: WeakEntity<Workspace>,
             cx: &mut App,
         ) -> AnyElement {
             let entity = entity.downcast::<T>().unwrap();
             entity.update(cx, |entity, cx| {
-                entity.render(status, window, cx).into_any_element()
+                entity
+                    .render(status, window, workspace, cx)
+                    .into_any_element()
             })
         }
 
@@ -102,8 +109,14 @@ impl<T: ToolCard> From<Entity<T>> for AnyToolCard {
 }
 
 impl AnyToolCard {
-    pub fn render(&self, status: &ToolUseStatus, window: &mut Window, cx: &mut App) -> AnyElement {
-        (self.render)(self.entity.clone(), status, window, cx)
+    pub fn render(
+        &self,
+        status: &ToolUseStatus,
+        window: &mut Window,
+        workspace: WeakEntity<Workspace>,
+        cx: &mut App,
+    ) -> AnyElement {
+        (self.render)(self.entity.clone(), status, window, workspace, cx)
     }
 }
 
@@ -163,6 +176,7 @@ pub trait Tool: 'static + Send + Sync {
         messages: &[LanguageModelRequestMessage],
         project: Entity<Project>,
         action_log: Entity<ActionLog>,
+        window: Option<AnyWindowHandle>,
         cx: &mut App,
     ) -> ToolResult;
 }