feat(ask): refine submission and custom answer flow

README.md

@@ -85,7 +85,7 @@ Use it when the agent needs structured clarification before proceeding.
       prompt: string,
       type?: "single" | "multi" | "code-review",
       allowOther?: boolean,
-      required?: boolean,
+      required?: boolean, // metadata only; submit is never blocked
       options: [
         {
           value: string,
@@ -150,7 +150,7 @@ The current prototype supports:
 - tabbed multi-question flow
 - single-select questions
 - multi-select questions
-- fixed `Type something.` fallback option
+- fixed `Type your own` fallback option that preserves typed text when dismissed
 - number-key quick selection
 - final submit/review page
 - transcript rendering for call/result rows