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/admin/usage/UsageExportProgress.vue

@@ -0,0 +1,16 @@
+<template>
+  <ExportProgressDialog
+    :show="show"
+    :progress="progress"
+    :current="current"
+    :total="total"
+    :estimated-time="estimatedTime"
+    @cancel="$emit('cancel')"
+  />
+</template>
+
+<script setup lang="ts">
+import ExportProgressDialog from '@/components/common/ExportProgressDialog.vue'
+defineProps<{ show: boolean, progress: number, current: number, total: number, estimatedTime: string }>()
+defineEmits(['cancel'])
+</script>