refactor(svelte5): migrate usePrefetch to $state

Refactor usePrefetch to use Svelte's $state instead of writable stores, simplifying state management and removing unnecessary imports. Update return values to use getters for compatibility with the new state approach.

Author: brodienguyen

packages/svelte5/src/usePrefetch.ts …ckages/svelte5/src/usePrefetch.svelte.tspackages/svelte5/src/usePrefetch.ts renamed to packages/svelte5/src/usePrefetch.svelte.ts packages/svelte5/src/usePrefetch.ts renamed to packages/svelte5/src/usePrefetch.svelte.ts

@@ -1,33 +1,32 @@
 import { router, type VisitOptions } from '@inertiajs/core'
 import { onDestroy, onMount } from 'svelte'
-import { readonly, writable } from 'svelte/store'
 
 export default function usePrefetch(options: VisitOptions = {}) {
-  const isPrefetched = writable(false)
-  const isPrefetching = writable(false)
-  const lastUpdatedAt = writable<number | null>(null)
+  let isPrefetched = $state(false)
+  let isPrefetching = $state(false)
+  let lastUpdatedAt = $state<number | null>(null)
 
   const cached = typeof window === 'undefined' ? null : router.getCached(window.location.pathname, options)
   const inFlight = typeof window === 'undefined' ? null : router.getPrefetching(window.location.pathname, options)
 
-  isPrefetched.set(cached !== null)
-  isPrefetching.set(inFlight !== null)
-  lastUpdatedAt.set(cached?.staleTimestamp || null)
+  isPrefetched = cached !== null
+  isPrefetching = inFlight !== null
+  lastUpdatedAt = cached?.staleTimestamp || null
 
   let removePrefetchedListener: () => void
   let removePrefetchingListener: () => void
 
   onMount(() => {
     removePrefetchingListener = router.on('prefetching', ({ detail }) => {
       if (detail.visit.url.pathname === window.location.pathname) {
-        isPrefetching.set(true)
+        isPrefetching = true
       }
     })
 
     removePrefetchedListener = router.on('prefetched', ({ detail }) => {
       if (detail.visit.url.pathname === window.location.pathname) {
-        isPrefetched.set(true)
-        isPrefetching.set(false)
+        isPrefetched = true
+        isPrefetching = false
       }
     })
   })
@@ -43,9 +42,15 @@ export default function usePrefetch(options: VisitOptions = {}) {
   })
 
   return {
-    isPrefetched: readonly(isPrefetched),
-    isPrefetching: readonly(isPrefetching),
-    lastUpdatedAt: readonly(lastUpdatedAt),
+    get isPrefetched() {
+      return isPrefetched
+    },
+    get isPrefetching() {
+      return isPrefetching
+    },
+    get lastUpdatedAt() {
+      return lastUpdatedAt
+    },
     flush() {
       router.flush(window.location.pathname, options)
     },