feat(admin): 优化后台运维与任务管理

完善平台、基准模型、定价规则和实时负载的紧凑查询与滚动展示，并固定关键操作列。

新增管理员任务记录、批量计费结算和用户组限流、额度及模型权限维护能力，同时补充任务脱敏、查询索引与 OpenAPI 契约。

验证：pnpm openapi、Go 全量测试、pnpm lint、pnpm test、pnpm build、gofmt 与差异格式检查均通过。

apps/web/src/routing.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { parseAppRoute, pathForApiDocSection } from './routing';
+import { defaultAdminTaskQuery, parseAppRoute, pathForAdminSection, pathForAdminTaskQuery, pathForApiDocSection } from './routing';
 
 describe('API documentation routes', () => {
   it.each([
@@ -35,3 +35,47 @@ describe('API documentation routes', () => {
     expect(parseAppRoute('/docs').apiDocSection).toBe('openApiOverview');
   });
 });
+
+describe('admin task routes', () => {
+  it('round-trips the complete admin task query through the URL', () => {
+    const query = {
+      ...defaultAdminTaskQuery(),
+      query: 'request-123',
+      tenantId: 'tenant-id',
+      userId: 'user-id',
+      userGroupId: 'group-id',
+      status: 'failed',
+      platformId: 'platform-id',
+      model: 'model-a',
+      modelType: 'image_generate',
+      runMode: 'production',
+      billingStatus: 'settled',
+      apiKey: 'ops-key',
+      createdFrom: '2026-07-01T00:00:00Z',
+      createdTo: '2026-07-25T00:00:00Z',
+      page: 3,
+      pageSize: 50,
+    };
+    const path = pathForAdminTaskQuery(query);
+    const parsed = parseAppRoute(path);
+    expect(parsed.adminSection).toBe('tasks');
+    expect(parsed.adminTaskQuery).toEqual(query);
+  });
+
+  it('uses stable defaults for the admin task page', () => {
+    expect(parseAppRoute('/admin/tasks').adminTaskQuery).toEqual(defaultAdminTaskQuery());
+  });
+});
+
+describe('admin billing settlement route', () => {
+  it('maps billing settlements to an independent admin page', () => {
+    expect(pathForAdminSection('billingSettlements')).toBe('/admin/billing-settlements');
+    expect(parseAppRoute('/admin/billing-settlements').adminSection).toBe('billingSettlements');
+  });
+});
+
+describe('legacy admin access rule route', () => {
+  it('opens user groups because model permissions are configured from the group row', () => {
+    expect(parseAppRoute('/admin/access-rules').adminSection).toBe('userGroups');
+  });
+});