Stable server fn endpoints: open tabs survive deploys

The 'previous question's resources until refresh' mystery: leptos's
auto-generated server fn routes embed a hash that changes across
builds. Every deploy therefore breaks every already-open tab - its
wasm keeps calling /api/get_question<oldhash>, the new server answers
400 'Could not find a server function at the route', and client-side
navigation quietly leaves the previous question's data on screen.
Refresh loads the new wasm with matching hashes, which is why it
always fixed it. Confirmed live: a pre-deploy client 400ed on
get_question2970801986613442004 while the freshly served wasm calls
get_question13103328088426240960, same source on both builds.

Explicit endpoint names decouple the URL from the build. This deploy
is the last breaking one; after it, old clients keep working.

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

src/answers.rs

@@ -101,7 +101,7 @@ pub struct TransitionItem {
 /// (the shared per-alternative Confirm button). Items are independent
 /// - per-item CAS, no cross-item transaction - so one failure doesn't
 /// roll back the others; failures are collected and reported together.
-#[server]
+#[server(endpoint = "transition_answers")]
 pub async fn transition_answers(
     question_id: String,
     alternative: String,
@@ -289,7 +289,7 @@ async fn apply_transition(
 /// itself. Deliberately returns the same generic error for "no such
 /// item" and "email doesn't match", so an unsubscribe link can't be
 /// used to probe which hashes or emails exist.
-#[server]
+#[server(endpoint = "self_transition_answer")]
 pub async fn self_transition_answer(
     question_id: String,
     alternative: String,