fix(app): keep timeline scroll when switching models (#50865)

packages/app/src/runtime/server/runtime.tsx

@@ -83,21 +83,21 @@ function createGlobalModels() {
     recent: [],
     variant: {},
   })
-  const [recent] = createResource(
-    async () => {
-      const value = store.recent
-      await ready.promise
-      return value
-    },
-    (value) => value,
-    { initialValue: [] },
-  )
+  // Suspend readers only until persisted state loads. Refetching on every change would put the
+  // session route into its Suspense fallback, detaching the screen and resetting the timeline scroll.
+  const [loaded] = createResource(async () => {
+    await ready.promise
+    return true
+  })
 
   return {
     store,
     set: setStore,
     ready,
-    recent: () => recent()!,
+    recent: () => {
+      loaded()
+      return store.recent
+    },
     // Marks models visible in the picker regardless of the "latest per family" default.
     show(models: ReadonlyArray<{ providerID: string; modelID: string }>) {
       const seen = new Map(store.user.map((item, index) => [`${item.providerID}:${item.modelID}`, index]))