Responsible note under the title; followup pages out of the nav until a chain exists

- The "Asked by X" line moves from the page footer to directly below
  the hero, where the question it belongs to is.
- New Question.followup flag: a post-submission page only appears in
  the question nav once the visitor's context actually carries an
  answer chain - nobody qualifies for "what happens now" before
  something happened.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app.rs

@@ -168,6 +168,8 @@ fn QuestionView(
     // on pages where some alternative actually declares a deck.
     let needs_swiper = question.alternatives.iter().any(|a| a.images.len() > 1);
 
+    let has_chain = parent_hash.is_some();
+
     view! {
         {needs_swiper.then(|| view! { <leptos_meta::Script src="/swiper-element-bundle.min.js"/> })}
         <Hero
@@ -175,6 +177,12 @@ fn QuestionView(
             description=question.description.clone()
             show_yes=question_id == "/"
         />
+        {question
+            .responsible
+            .clone()
+            .map(|r| {
+                view! { <ResponsibleNote responsible=r/> }
+            })}
         <div class="alternatives">
             <For
                 each={
@@ -212,13 +220,7 @@ fn QuestionView(
                 }
             />
         </div>
-        <QuestionNav current_id=question_id/>
-        {question
-            .responsible
-            .clone()
-            .map(|r| {
-                view! { <ResponsibleNote responsible=r/> }
-            })}
+        <QuestionNav current_id=question_id has_chain=has_chain/>
     }
     .into_any()
 }
@@ -227,8 +229,8 @@ fn QuestionView(
 /// small nav - how a concern reaches the people it speaks to without
 /// claiming front-page space (an owner also sees the gated desks here).
 #[component]
-fn QuestionNav(current_id: String) -> impl IntoView {
-    let nav = Resource::new(|| (), |_| list_qualifying_questions());
+fn QuestionNav(current_id: String, has_chain: bool) -> impl IntoView {
+    let nav = Resource::new(move || has_chain, list_qualifying_questions);
     view! {
         <Suspense fallback=|| ()>
             {move || {
@@ -1432,9 +1434,12 @@ pub async fn get_question(path: String) -> Result<Option<Question>, ServerFnErro
 
 /// Every question the current visitor qualifies for, as (id, name) -
 /// the site nav's data. Context-dependent: an owner session sees the
-/// gated pages too, an anonymous visitor only the public ones.
+/// gated pages too, and `followup` pages only appear once the visitor
+/// carries an answer chain.
 #[server]
-pub async fn list_qualifying_questions() -> Result<Vec<(String, String)>, ServerFnError> {
+pub async fn list_qualifying_questions(
+    has_chain: bool,
+) -> Result<Vec<(String, String)>, ServerFnError> {
     use crate::auth::{User, SESSION_USER_KEY};
     use crate::content::is_qualified;
     use crate::server::AppState;
@@ -1451,6 +1456,7 @@ pub async fn list_qualifying_questions() -> Result<Vec<(String, String)>, Server
         .load()
         .values()
         .filter(|q| is_qualified(user.as_ref(), q))
+        .filter(|q| !q.followup || has_chain)
         .map(|q| (q.id.clone(), q.name.clone()))
         .collect();
     out.sort();