Persist viewport dimensions in a cookie so SSR renders full-height grid skeletons

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

app/composables/usePageSize.ts

@@ -5,6 +5,8 @@ import { useWindowSize } from '@vueuse/core'
 // grid-cols-4 sm:6 md:8 lg:12, auto-rows 6.5rem / sm:7rem / lg:7.5rem, gap-2
 const PAGINATION_RESERVE_PX = 60 // Pagination (~36px) + pt-4, knapp bemessen damit die letzte Zeile nicht wegfällt
 const FALLBACK_TOP_PX = 150 // SSR-Schätzung: Header + Padding + Filterzeile
+const DEFAULT_SSR_WIDTH = 1920
+const DEFAULT_SSR_HEIGHT = 1080
 
 interface PageSizeOptions {
   // [base, sm (>=640px), lg (>=1024px)] — Zeilenhöhe in rem ohne Grid-Gap
@@ -15,10 +17,26 @@ interface PageSizeOptions {
 
 export function usePageSize(anchor: Ref<HTMLElement | null | undefined>, options: PageSizeOptions = {}) {
   const { rowHeights = [6.5, 7, 7.5], gapBelowAnchorPx = 8 } = options
-  const { width, height } = useWindowSize()
+  const savedVp = useCookie<{ w: number, h: number }>('vp-size', {
+    default: () => ({ w: DEFAULT_SSR_WIDTH, h: DEFAULT_SSR_HEIGHT }),
+    sameSite: 'lax',
+  })
+  const { width, height } = useWindowSize({
+    initialWidth: savedVp.value?.w || DEFAULT_SSR_WIDTH,
+    initialHeight: savedVp.value?.h || DEFAULT_SSR_HEIGHT,
+  })
+  if (import.meta.client) {
+    watch([width, height], ([w, h]) => {
+      if (Number.isFinite(w) && Number.isFinite(h) && w > 0 && h > 0) {
+        if (savedVp.value?.w !== w || savedVp.value?.h !== h) {
+          savedVp.value = { w, h }
+        }
+      }
+    }, { immediate: true })
+  }
 
   const cols = computed(() => {
-    const w = Number.isFinite(width.value) ? width.value : 1280
+    const w = Number.isFinite(width.value) ? width.value : (savedVp.value?.w || DEFAULT_SSR_WIDTH)
     return w >= 1024 ? 12 : w >= 768 ? 8 : w >= 640 ? 6 : 4
   })
 
@@ -59,8 +77,8 @@ export function usePageSize(anchor: Ref<HTMLElement | null | undefined>, options
   watch([width, height], measureAnchor, { flush: 'post' })
 
   const cells = computed(() => {
-    const w = Number.isFinite(width.value) ? width.value : 1280
-    const h = Number.isFinite(height.value) ? height.value : 800
+    const w = Number.isFinite(width.value) ? width.value : (savedVp.value?.w || DEFAULT_SSR_WIDTH)
+    const h = Number.isFinite(height.value) ? height.value : (savedVp.value?.h || DEFAULT_SSR_HEIGHT)
     const rem = import.meta.client
       ? Number.parseFloat(getComputedStyle(document.documentElement).fontSize) || 16
       : 16