add comments to everything potentially consumer facing

sdk/base/lib/util/getDefaultString.ts

@@ -1,6 +1,14 @@
 import { DefaultString } from '../actions/input/inputSpecTypes'
 import { getRandomString } from './getRandomString'
 
+/**
+ * Resolves a DefaultString spec into a concrete string value.
+ * If the spec is a plain string, returns it directly.
+ * If it is a random-string specification, generates a random string accordingly.
+ *
+ * @param defaultSpec - A string literal or a random-string generation spec
+ * @returns The resolved default string value
+ */
 export function getDefaultString(defaultSpec: DefaultString): string {
   if (typeof defaultSpec === 'string') {
     return defaultSpec