fix : use correct useToast() API in export handler

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/pages/time-tracking.vue

@@ -325,10 +325,10 @@ async function onExport(params: {
     client?: number
     tags?: number[]
 }) {
-    const { success, error } = useToast()
+    const toast = useToast()
     const { t } = useNuxtApp().$i18n as { t: (key: string) => string }
 
-    success(t('timeEntries.exportLoading'))
+    toast.info({ message: t('timeEntries.exportLoading') })
 
     try {
         const result = await timeEntryService.downloadExport(params)
@@ -342,9 +342,9 @@ async function onExport(params: {
         document.body.removeChild(a)
         URL.revokeObjectURL(url)
 
-        success(t('timeEntries.exportSuccess'))
+        toast.success({ message: t('timeEntries.exportSuccess') })
     } catch {
-        error(t('timeEntries.exportError'))
+        toast.error({ message: t('timeEntries.exportError') })
     }
 }