add docstrings

src/main/frontend/util/js_module.cljs

@@ -1,7 +1,9 @@
 (ns frontend.util.js-module
+  "Helpers for reading JavaScript module exports across ESM, CommonJS interop, and bundled namespace objects."
   (:require [goog.object :as gobj]))
 
 (defn default-export
+  "Returns the callable/default value from ESM, CommonJS interop, or namespace-shaped modules."
   [module]
   (or (when (some? module)
         (gobj/get module "default"))