Apply suggestions from code review

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: simongdavies

src/hyperlight-js/src/sandbox/proto_js_sandbox.rs

@@ -149,7 +149,14 @@ impl ProtoJSSandbox {
                 let module = host_modules
                     .get(&module_name)
                     .ok_or_else(|| new_error!("Host module '{}' not found", module_name))?;
-                module.call(&func_name, args_json, Some(binaries))
+                module
+                    .call(&func_name, args_json, Some(binaries))
+                    .map_err(|e| {
+                        e.context(format!(
+                            "Error calling host function '{}' in module '{}'",
+                            func_name, module_name
+                        ))
+                    })
             },
         )?;
 

src/js-host-api/src/lib.rs

@@ -686,7 +686,7 @@ unsafe fn json_to_napi_with_buffers(
                     napi::sys::napi_create_string_utf8(
                         env,
                         key_bytes.as_ptr().cast(),
-                        key_bytes.len() as isize,
+                        key_bytes.len(),
                         &mut key_val,
                     )
                 };