fix: improve session management and UI highlights

components/settings/SecurityActivityCard.tsx

@@ -4,6 +4,7 @@ import { useEffect, useState, useCallback } from 'react'
 import { useAuth } from '@/lib/auth/context'
 import { getUserActivity, type AuditLogEntry } from '@/lib/api/activity'
 import { Spinner } from '@ciphera-net/ui'
+import { formatRelativeTime, formatFullDate } from '@/lib/utils/formatDate'
 
 const PAGE_SIZE = 20
 
@@ -62,37 +63,6 @@ function getFailureReason(entry: AuditLogEntry): string | null {
   return labels[reason as string] || (reason as string).replace(/_/g, ' ')
 }
 
-function formatRelativeTime(dateStr: string): string {
-  const date = new Date(dateStr)
-  const now = new Date()
-  const diffMs = now.getTime() - date.getTime()
-  const diffMin = Math.floor(diffMs / 60000)
-  const diffHr = Math.floor(diffMin / 60)
-  const diffDay = Math.floor(diffHr / 24)
-
-  if (diffMin < 1) return 'Just now'
-  if (diffMin < 60) return `${diffMin}m ago`
-  if (diffHr < 24) return `${diffHr}h ago`
-  if (diffDay < 7) return `${diffDay}d ago`
-
-  return date.toLocaleDateString('en-US', {
-    month: 'short',
-    day: 'numeric',
-    year: date.getFullYear() !== now.getFullYear() ? 'numeric' : undefined,
-  })
-}
-
-function formatFullDate(dateStr: string): string {
-  return new Date(dateStr).toLocaleString('en-US', {
-    weekday: 'short',
-    month: 'short',
-    day: 'numeric',
-    year: 'numeric',
-    hour: 'numeric',
-    minute: '2-digit',
-  })
-}
-
 function parseBrowserName(ua: string): string {
   if (!ua) return 'Unknown'
   if (ua.includes('Firefox')) return 'Firefox'