Revalidating cache on app assets; site title survives SPA navigation

pkg files keep stable names across releases, so an uncontrolled
browser cache could pair last release's wasm with the new server's
server-fn wire format - every page then renders its error branch
(redoal.com's 'Nothing here' after v0.2.0). Cache-Control: no-cache
on /pkg and /yes.js makes clients revalidate (a 304 per load) instead
of guessing. The content-declared site title also moves out of the
question Suspense: remounting with each navigation lost the
leptos_meta race to the compile-time fallback, flipping redoal.com's
tab to 'uhhm' on the first client-side nav.

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

src/main.rs

@@ -143,7 +143,22 @@ async fn main() -> anyhow::Result<()> {
         .route("/upload", post(upload::upload))
         .route("/gitea-repo", get(content::gitea_repo_handler))
         .route("/automation/kv/{bucket}", get(content::automation_kv_handler))
-        .nest_service("/pkg", ServeDir::new(pkg_dir))
+        // no-cache = "revalidate before reuse", not "don't cache":
+        // pkg files keep the same names across releases (portal.js,
+        // portal.wasm), and without this browsers heuristically cache
+        // them - a stale wasm from the previous release then talks to
+        // a server whose server-fn wire format has moved on and every
+        // page renders as its error branch. A 304 per load is the
+        // price of never shipping that skew again.
+        .nest_service(
+            "/pkg",
+            tower::ServiceBuilder::new()
+                .layer(tower_http::set_header::SetResponseHeaderLayer::overriding(
+                    axum::http::header::CACHE_CONTROL,
+                    axum::http::HeaderValue::from_static("no-cache"),
+                ))
+                .service(ServeDir::new(pkg_dir)),
+        )
         .nest_service("/fonts", ServeDir::new(fonts_dir))
         .route_service("/favicon-light.svg", ServeFile::new(favicon_light_path))
         .route_service("/favicon-dark.svg", ServeFile::new(favicon_dark_path))
@@ -152,7 +167,17 @@ async fn main() -> anyhow::Result<()> {
             "/swiper-element-bundle.min.js",
             ServeFile::new(swiper_path),
         )
-        .route_service("/yes.js", ServeFile::new(yes_path))
+        // Same skew concern as /pkg: the wasm's raw_module import and
+        // the hero's inline script both load this by fixed name.
+        .route_service(
+            "/yes.js",
+            tower::ServiceBuilder::new()
+                .layer(tower_http::set_header::SetResponseHeaderLayer::overriding(
+                    axum::http::header::CACHE_CONTROL,
+                    axum::http::HeaderValue::from_static("no-cache"),
+                ))
+                .service(ServeFile::new(yes_path)),
+        )
         .leptos_routes_with_context(
             &state,
             routes,