docs: fix SSG build errors in date example and playground

- Remove invalid firstDayOfWeek arg from getWeekdays call in calendar example
- Guard window access with IN_BROWSER in playground redirect page
- Correct getWeekdays signature in use-date docs

Author: johnleider

apps/docs/src/examples/composables/use-date/calendar.vue

@@ -5,7 +5,7 @@
   const { adapter } = useDate()
 
   const current = shallowRef(adapter.date()!)
-  const weekdays = computed(() => adapter.getWeekdays(0, 'narrow'))
+  const weekdays = computed(() => adapter.getWeekdays('narrow'))
   const weeks = computed(() => {
     const allWeeks = adapter.getWeekArray(current.value)
     // Always show exactly 5 weeks for consistent height

apps/docs/src/pages/composables/plugins/use-date.md

@@ -167,7 +167,7 @@ interface DateAdapter<T> {
   setSeconds (date: T, seconds: number): T
 
   // Calendar Utilities
-  getWeekdays (firstDayOfWeek?: number, format?: 'long' | 'short' | 'narrow'): string[]
+  getWeekdays (format?: 'long' | 'short' | 'narrow'): string[]
   getWeekArray (date: T, firstDayOfWeek?: number): T[][]
   getMonthArray (date: T): T[]
   getYearRange (start: T, end: T): T[]

apps/docs/src/pages/playground.vue

@@ -3,7 +3,7 @@
   import { useHead } from '@unhead/vue'
 
   const target = import.meta.env.VITE_PLAYGROUND_URL ?? 'https://v0play.vuetifyjs.com'
-  const redirect = `${target}/${window?.location?.hash ?? ''}`
+  const redirect = `${target}/${IN_BROWSER ? window.location.hash : ''}`
 
   definePage({
     meta: {