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/app.rs

@@ -1484,7 +1484,7 @@ fn NotFound() -> impl IntoView {
     }
 }
 
-#[server]
+#[server(endpoint = "get_question")]
 pub async fn get_question(path: String) -> Result<Option<Question>, ServerFnError> {
     use crate::server::AppState;
     let state = expect_context::<AppState>();
@@ -1495,7 +1495,7 @@ pub async fn get_question(path: String) -> Result<Option<Question>, ServerFnErro
 /// the site nav's data. Context-dependent: an owner session sees the
 /// gated pages too, and `followup` pages only appear once the visitor
 /// carries an answer chain.
-#[server]
+#[server(endpoint = "list_qualifying_questions")]
 pub async fn list_qualifying_questions(
     has_chain: bool,
 ) -> Result<Vec<(String, String)>, ServerFnError> {
@@ -1528,7 +1528,7 @@ pub struct SubmitResult {
     pub chain_hash: String,
 }
 
-#[server]
+#[server(endpoint = "submit_answer")]
 pub async fn submit_answer(
     question_id: String,
     alternative: String,