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>

frontend/src/components/admin/usage/UsageFilters.vue

@@ -0,0 +1,35 @@
+<template>
+  <div class="card p-6"><div class="flex flex-wrap items-end gap-4">
+    <div class="min-w-[200px] relative"><label class="input-label">{{ t('admin.usage.userFilter') }}</label>
+      <input v-model="userKW" type="text" class="input pr-8" :placeholder="t('admin.usage.searchUserPlaceholder')" @input="debounceSearch" @focus="showDD = true" />
+      <button v-if="modelValue.user_id" @click="clearUser" class="absolute right-2 top-9 text-gray-400">✕</button>
+      <div v-if="showDD && (results.length > 0 || userKW)" class="absolute z-50 mt-1 max-h-60 w-full overflow-auto rounded-lg border bg-white shadow-lg dark:bg-gray-800">
+        <button v-for="u in results" :key="u.id" @click="selectUser(u)" class="w-full px-4 py-2 text-left hover:bg-gray-100 dark:hover:bg-gray-700"><span>{{ u.email }}</span><span class="ml-2 text-xs text-gray-400">#{{ u.id }}</span></button>
+      </div>
+    </div>
+    <div class="min-w-[180px]"><label class="input-label">{{ t('usage.model') }}</label><Select v-model="filters.model" :options="mOpts" searchable @change="emitChange" /></div>
+    <div class="min-w-[150px]"><label class="input-label">{{ t('admin.usage.group') }}</label><Select v-model="filters.group_id" :options="gOpts" @change="emitChange" /></div>
+    <div><label class="input-label">{{ t('usage.timeRange') }}</label><DateRangePicker :start-date="startDate" :end-date="endDate" @update:startDate="$emit('update:startDate', $event)" @update:endDate="$emit('update:endDate', $event)" @change="emitChange" /></div>
+    <div class="ml-auto flex gap-3"><button @click="$emit('reset')" class="btn btn-secondary">{{ t('common.reset') }}</button><button @click="$emit('export')" :disabled="exporting" class="btn btn-primary">{{ t('usage.exportExcel') }}</button></div>
+  </div></div>
+</template>
+
+<script setup lang="ts">
+import { ref, computed, onMounted, onUnmounted, reactive } from 'vue'; import { useI18n } from 'vue-i18n'; import { adminAPI } from '@/api/admin'; import Select from '@/components/common/Select.vue'; import DateRangePicker from '@/components/common/DateRangePicker.vue'
+const props = defineProps(['modelValue', 'exporting', 'startDate', 'endDate']); const emit = defineEmits(['update:modelValue', 'update:startDate', 'update:endDate', 'change', 'reset', 'export'])
+const { t } = useI18n(); const filters = props.modelValue
+const userKW = ref(''); const results = ref<any[]>([]); const showDD = ref(false); let timeout: any = null
+const mOpts = ref([{ value: null, label: t('admin.usage.allModels') }]); const gOpts = ref([{ value: null, label: t('admin.usage.allGroups') }])
+const emitChange = () => emit('change')
+const debounceSearch = () => { clearTimeout(timeout); timeout = setTimeout(async () => { if(!userKW.value) { results.value = []; return }; try { results.value = await adminAPI.usage.searchUsers(userKW.value) } catch {} }, 300) }
+const selectUser = (u: any) => { userKW.value = u.email; showDD.value = false; filters.user_id = u.id; emitChange() }
+const clearUser = () => { userKW.value = ''; results.value = []; filters.user_id = undefined; emitChange() }
+onMounted(async () => {
+  try { const [gs, ms] = await Promise.all([adminAPI.groups.list(1, 1000), adminAPI.dashboard.getModelStats({ start_date: props.startDate, end_date: props.endDate })])
+    gOpts.value.push(...gs.items.map((g: any) => ({ value: g.id, label: g.name })))
+    const unique = new Set<string>(); ms.models?.forEach((s: any) => s.model && unique.add(s.model))
+    mOpts.value.push(...Array.from(unique).sort().map(m => ({ value: m, label: m })))
+  } catch {}
+  document.addEventListener('click', (e) => { if(!(e.target as HTMLElement).closest('.relative')) showDD.value = false })
+})
+</script>

frontend/src/components/admin/usage/UsageStatsCards.vue

@@ -0,0 +1,27 @@
+<template>
+  <div class="grid grid-cols-2 gap-4 lg:grid-cols-4">
+    <div class="card p-4 flex items-center gap-3">
+      <div class="rounded-lg bg-blue-100 p-2 dark:bg-blue-900/30 text-blue-600"><svg class="h-5 w-5" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 12h6m-6 4h6m2 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" /></svg></div>
+      <div><p class="text-xs font-medium text-gray-500">{{ t('usage.totalRequests') }}</p><p class="text-xl font-bold">{{ stats?.total_requests?.toLocaleString() || '0' }}</p></div>
+    </div>
+    <div class="card p-4 flex items-center gap-3">
+      <div class="rounded-lg bg-amber-100 p-2 dark:bg-amber-900/30 text-amber-600"><svg class="h-5 w-5" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="m21 7.5-9-5.25L3 7.5m18 0-9 5.25m9-5.25v9l-9 5.25M3 7.5l9 5.25M3 7.5v9l9 5.25m0-9v9" /></svg></div>
+      <div><p class="text-xs font-medium text-gray-500">{{ t('usage.totalTokens') }}</p><p class="text-xl font-bold">{{ formatTokens(stats?.total_tokens || 0) }}</p></div>
+    </div>
+    <div class="card p-4 flex items-center gap-3">
+      <div class="rounded-lg bg-green-100 p-2 dark:bg-green-900/30 text-green-600"><svg class="h-5 w-5" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 8c-1.657 0-3 .895-3 2s1.343 2 3 2 3 .895 3 2-1.343 2-3 2m0-8c1.11 0 2.08.402 2.599 1M12 8V7m0 1v8m0 0v1m0-1c-1.11 0-2.08-.402-2.599-1M21 12a9 9 0 11-18 0 9 9 0 0118 0z" /></svg></div>
+      <div><p class="text-xs font-medium text-gray-500">{{ t('usage.totalCost') }}</p><p class="text-xl font-bold text-green-600">${{ (stats?.total_actual_cost || 0).toFixed(4) }}</p></div>
+    </div>
+    <div class="card p-4 flex items-center gap-3">
+      <div class="rounded-lg bg-purple-100 p-2 dark:bg-purple-900/30 text-purple-600"><svg class="h-5 w-5" fill="none" stroke="currentColor" viewBox="0 0 24 24"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 6v6h4.5m4.5 0a9 9 0 11-18 0 9 9 0 0118 0z" /></svg></div>
+      <div><p class="text-xs font-medium text-gray-500">{{ t('usage.avgDuration') }}</p><p class="text-xl font-bold">{{ formatDuration(stats?.average_duration_ms || 0) }}</p></div>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { useI18n } from 'vue-i18n'; import type { AdminUsageStatsResponse } from '@/api/admin/usage'
+defineProps<{ stats: AdminUsageStatsResponse | null }>(); const { t } = useI18n()
+const formatDuration = (ms: number) => ms < 1000 ? `${ms.toFixed(0)}ms` : `${(ms/1000).toFixed(2)}s`
+const formatTokens = (v: number) => { if (v >= 1e9) return (v/1e9).toFixed(2) + 'B'; if (v >= 1e6) return (v/1e6).toFixed(2) + 'M'; if (v >= 1e3) return (v/1e3).toFixed(2) + 'K'; return v.toLocaleString() }
+</script>

frontend/src/components/admin/usage/UsageTable.vue

@@ -0,0 +1,22 @@
+<template>
+  <div class="card overflow-hidden"><div class="overflow-auto">
+    <DataTable :columns="cols" :data="data" :loading="loading">
+      <template #cell-user="{ row }"><div class="text-sm"><span class="font-medium text-gray-900 dark:text-white">{{ row.user?.email || '-' }}</span><span class="ml-1 text-xs text-gray-400">#{{ row.user_id }}</span></div></template>
+      <template #cell-model="{ value }"><span class="font-medium">{{ value }}</span></template>
+      <template #cell-tokens="{ row }"><div class="text-sm">In: {{ row.input_tokens.toLocaleString() }} / Out: {{ row.output_tokens.toLocaleString() }}</div></template>
+      <template #cell-cost="{ row }"><span class="font-medium text-green-600">${{ row.actual_cost.toFixed(6) }}</span></template>
+      <template #cell-created_at="{ value }"><span class="text-sm text-gray-500">{{ formatDateTime(value) }}</span></template>
+      <template #empty><EmptyState :message="t('usage.noRecords')" /></template>
+    </DataTable>
+  </div></div>
+</template>
+
+<script setup lang="ts">
+import { computed } from 'vue'; import { useI18n } from 'vue-i18n'; import { formatDateTime } from '@/utils/format'; import DataTable from '@/components/common/DataTable.vue'; import EmptyState from '@/components/common/EmptyState.vue'
+defineProps(['data', 'loading']); const { t } = useI18n()
+const cols = computed(() => [
+  { key: 'user', label: t('admin.usage.user') }, { key: 'model', label: t('usage.model'), sortable: true },
+  { key: 'tokens', label: t('usage.tokens') }, { key: 'cost', label: t('usage.cost') },
+  { key: 'created_at', label: t('usage.time'), sortable: true }
+])
+</script>