Add initial scripting_tool (#26066)

Just a basic implementation so we can start trying it out.

Release Notes:

- N/A

---------

Co-authored-by: Marshall <marshall@zed.dev>
Co-authored-by: Michael <michael@zed.dev>

crates/zed/src/main.rs

@@ -477,6 +477,7 @@ fn main() {
             cx,
         );
         assistant_tools::init(cx);
+        scripting_tool::init(cx);
         repl::init(app_state.fs.clone(), cx);
         extension_host::init(
             extension_host_proxy,