perf(usage): 优化 /admin/usage 打开速度与刷新响应

根因:页面 mount 并发 6 个请求,其中 5 个在原始 usage_logs 上 live 聚合,
且有 1 个重复 getModelStats。优化(不引入预聚合):

前端
- UsageView 经 :model-options 下传 model 列表,移除 UsageFilters 重复的
  getModelStats(mount 请求 6→5,少一次 usage_logs 全表 GROUP BY model)
- 刷新/换筛选保留旧模型数据(invalidateModelStatsCache 只失效标记不清空数据),
  图表不再闪空,刷新期间页面保持可交互

后端
- GetStatsWithFilters 4 条聚合 errgroup 并行(仅 *sql.DB 连接池路径,ent.Tx
  顺序回退以保事务内不并发),endpoint 明细 best-effort;抑制取消级联噪声日志
- /admin/usage/stats 复用 dashboard 的 newSnapshotCache 30s 处理器层缓存,按
  filters+窗口为 key;前端手动刷新带 nocache=1 强制回源(刷新=最新)

注:自合并提交 4c8396c 迁移而来,仅取"列表打开速度与刷新响应"部分;原提交的
"审计查看弹窗大 body 渲染"改动(AuditLogModal / audit-log-format / 审计 i18n)
依赖尚未迁移的审计功能(d8389ade),本次已排除。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/components/admin/usage/__tests__/UsageFilters.spec.ts

@@ -50,6 +50,9 @@ vi.mock('vue-i18n', async () => {
 // Mock the admin API module — we control searchUsers return value per test
 const mockSearchUsers = vi.fn()
 const mockSearchApiKeys = vi.fn().mockResolvedValue([])
+const mockGroupsList = vi.fn().mockResolvedValue({ items: [] })
+const mockGetModelStats = vi.fn().mockResolvedValue({ models: [] })
+const mockAccountsList = vi.fn().mockResolvedValue({ items: [] })
 
 vi.mock('@/api/admin', () => ({
   adminAPI: {
@@ -57,15 +60,9 @@ vi.mock('@/api/admin', () => ({
       searchUsers: (...args: any[]) => mockSearchUsers(...args),
       searchApiKeys: (...args: any[]) => mockSearchApiKeys(...args),
     },
-    groups: {
-      list: vi.fn().mockResolvedValue({ items: [] }),
-    },
-    dashboard: {
-      getModelStats: vi.fn().mockResolvedValue({ models: [] }),
-    },
-    accounts: {
-      list: vi.fn().mockResolvedValue({ items: [] }),
-    },
+    groups: { list: (...args: any[]) => mockGroupsList(...args) },
+    dashboard: { getModelStats: (...args: any[]) => mockGetModelStats(...args) },
+    accounts: { list: (...args: any[]) => mockAccountsList(...args) },
   },
 }))
 
@@ -91,6 +88,7 @@ function mountFilters(filters = defaultFilters()) {
       startDate: '2026-05-01',
       endDate: '2026-05-28',
       showActions: false,
+      modelOptions: [],
     },
     global: {
       stubs: {
@@ -166,3 +164,32 @@ describe('UsageFilters — user search dropdown', () => {
     expect(wrapper.props('modelValue').user_id).toBe(1)
   })
 })
+
+describe('UsageFilters — model options come from prop (no dup request)', () => {
+  beforeEach(() => {
+    vi.useFakeTimers()
+    mockGetModelStats.mockClear()
+    mockGroupsList.mockClear()
+  })
+  afterEach(() => { vi.useRealTimers() })
+
+  it('does not call dashboard.getModelStats on mount and renders model options from prop', async () => {
+    const wrapper = mount(UsageFilters, {
+      props: {
+        modelValue: defaultFilters(),
+        exporting: false,
+        startDate: '2026-05-01',
+        endDate: '2026-05-28',
+        showActions: false,
+        modelOptions: ['claude-3', 'gpt-4o'],
+      },
+      global: { stubs: { Select: true, Teleport: true } },
+    })
+    await flushPromises()
+
+    expect(mockGetModelStats).not.toHaveBeenCalled()
+
+    const opts = (wrapper.vm as any).modelOptions as Array<{ value: string | null; label: string }>
+    expect(opts.map((o) => o.value)).toEqual([null, 'claude-3', 'gpt-4o'])
+  })
+})