Add ListDirectoryTool (#26549)

Release Notes:

- N/A

crates/assistant_tools/src/assistant_tools.rs

@@ -1,4 +1,5 @@
 mod edit_files_tool;
+mod list_directory_tool;
 mod now_tool;
 mod read_file_tool;
 
@@ -6,6 +7,7 @@ use assistant_tool::ToolRegistry;
 use gpui::App;
 
 use crate::edit_files_tool::EditFilesTool;
+use crate::list_directory_tool::ListDirectoryTool;
 use crate::now_tool::NowTool;
 use crate::read_file_tool::ReadFileTool;
 
@@ -15,5 +17,6 @@ pub fn init(cx: &mut App) {
     let registry = ToolRegistry::global(cx);
     registry.register_tool(NowTool);
     registry.register_tool(ReadFileTool);
+    registry.register_tool(ListDirectoryTool);
     registry.register_tool(EditFilesTool);
 }