refactor(frontend): comprehensive split of large view files into modular components

- Split UsersView.vue into UserCreateModal, UserEditModal, UserApiKeysModal, etc.
- Split UsageView.vue into UsageStatsCards, UsageFilters, UsageTable, etc.
- Split DashboardView.vue into UserDashboardStats, UserDashboardCharts, etc.
- Split AccountsView.vue into AccountTableActions, AccountTableFilters, etc.
- Standardized TypeScript types across new components to resolve implicit 'any' and 'never[]' errors.
- Improved overall frontend maintainability and code clarity.

frontend/src/components/user/dashboard/UserDashboardQuickActions.vue

@@ -0,0 +1,15 @@
+<template>
+  <div class="card p-6">
+    <h2 class="font-semibold mb-4">{{ t('dashboard.quickActions') }}</h2>
+    <div class="space-y-2">
+      <button @click="router.push('/keys')" class="w-full text-left p-3 hover:bg-gray-100 rounded-lg flex items-center gap-3"><div class="p-2 bg-blue-100 rounded-lg text-blue-600">🔑</div><span>{{ t('dashboard.createApiKey') }}</span></button>
+      <button @click="router.push('/usage')" class="w-full text-left p-3 hover:bg-gray-100 rounded-lg flex items-center gap-3"><div class="p-2 bg-green-100 rounded-lg text-green-600">📊</div><span>{{ t('dashboard.viewUsage') }}</span></button>
+      <button @click="router.push('/redeem')" class="w-full text-left p-3 hover:bg-gray-100 rounded-lg flex items-center gap-3"><div class="p-2 bg-amber-100 rounded-lg text-amber-600">🎁</div><span>{{ t('dashboard.redeemCode') }}</span></button>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { useRouter } from 'vue-router'; import { useI18n } from 'vue-i18n'
+const router = useRouter(); const { t } = useI18n()
+</script>