refactor(app): simplify session routing and tab close handling (#28767)

packages/app/src/app.tsx

@@ -48,22 +48,17 @@ import { ErrorPage } from "./pages/error"
 import { useCheckServerHealth } from "./utils/server-health"
 
 const HomeRoute = lazy(() => import("@/pages/home"))
-const loadSession = () => import("@/pages/session")
-const Session = lazy(loadSession)
-const Loading = () => <div class="size-full" />
+const Session = lazy(() => import("@/pages/session"))
 
-if (typeof location === "object" && /\/session(?:\/|$)/.test(location.pathname)) {
-  void loadSession()
-}
-
-const SessionRoute = () => (
-  <SessionProviders>
-    <Session />
-  </SessionProviders>
+const SessionRoute = Object.assign(
+  () => (
+    <SessionProviders>
+      <Session />
+    </SessionProviders>
+  ),
+  { preload: Session.preload },
 )
 
-const SessionIndexRoute = () => <Navigate href="session" />
-
 function UiI18nBridge(props: ParentProps) {
   const language = useLanguage()
   return <I18nProvider value={{ locale: language.intl, t: language.t }}>{props.children}</I18nProvider>
@@ -317,7 +312,7 @@ export function AppInterface(props: {
                 >
                   <Route path="/" component={HomeRoute} />
                   <Route path="/:dir" component={DirectoryLayout}>
-                    <Route path="/" component={SessionIndexRoute} />
+                    <Route path="/" component={() => <Navigate href="session" />} />
                     <Route path="/session/:id?" component={SessionRoute} />
                   </Route>
                 </Dynamic>