refactor(react-router): useMatches skips useRef during SSR (#7575)

Author: Sheraff

.changeset/four-carrots-post.md

@@ -0,0 +1,5 @@
+---
+'@tanstack/react-router': patch
+---
+
+useMatches can skip useRef for structural sharing during SSR

packages/react-router/src/Matches.tsx

@@ -234,10 +234,6 @@ export function useMatches<
     StructuralSharingOption<TRouter, TSelected, TStructuralSharing>,
 ): UseMatchesResult<TRouter, TSelected> {
   const router = useRouter<TRouter>()
-  const previousResult =
-    React.useRef<ValidateSelected<TRouter, TSelected, TStructuralSharing>>(
-      undefined,
-    )
 
   if (isServer ?? router.isServer) {
     const matches = router.stores.matches.get() as Array<
@@ -249,6 +245,12 @@ export function useMatches<
     >
   }
 
+  const previousResult =
+    // eslint-disable-next-line react-hooks/rules-of-hooks
+    React.useRef<ValidateSelected<TRouter, TSelected, TStructuralSharing>>(
+      undefined,
+    )
+
   // eslint-disable-next-line react-hooks/rules-of-hooks
   return useStore(router.stores.matches, (matches) => {
     const selected = opts?.select