采集任务支持手动触发 + 定时调度(cron)

后端:
- 新增 Scheduler + ScheduledTask 核心模块(croniter 解析 cron 表达式)
- 新增 Schedule 数据模型(alembic 0016)
- 新增 /api/v1/admin/schedules CRUD 接口
- lifespan 启动时注册默认定时任务并加载数据库配置
- 默认任务:每日比赛/积分榜/30分钟统计回填(默认禁用)

前端:
- 设置页新增「定时任务」管理区块
- 支持:新建/启用禁用/立即执行/删除定时任务
- 显示:任务ID、类型、cron表达式、上次执行时间/状态

依赖:新增 croniter>=2.0

Co-Authored-By: new-provider/LongCat-2.0 <<EMAIL>>

frontend/src/admin/dal.ts

@@ -406,3 +406,35 @@ export async function fetchKeyRingStatus(): Promise<KeyRingStatusResponse> {
 export async function resetKeyRingCooldown(): Promise<{ ok: boolean; message: string; stats: KeyRingStatusResponse }> {
   return api.post<{ ok: boolean; message: string; stats: KeyRingStatusResponse }>(`${API_BASE}/admin/keyring/cooldown/reset`)
 }
+
+// ── 定时任务 ────────────────────────────────────────────────────
+
+export interface ScheduleItem {
+  id: string
+  task: string
+  cron: string
+  leagues?: string
+  enabled: boolean
+  last_run_at?: string | null
+  last_status?: string | null
+}
+
+export async function fetchSchedules(): Promise<ScheduleItem[]> {
+  return api.get<ScheduleItem[]>(`${API_BASE}/admin/schedules`)
+}
+
+export async function createSchedule(data: { id: string; task: string; cron: string; leagues?: string; enabled: boolean }): Promise<{ ok: boolean }> {
+  return api.post<{ ok: boolean }>(`${API_BASE}/admin/schedules`, data)
+}
+
+export async function updateSchedule(id: string, data: Partial<ScheduleItem>): Promise<{ ok: boolean }> {
+  return api.put<{ ok: boolean }>(`${API_BASE}/admin/schedules/${id}`, data)
+}
+
+export async function deleteSchedule(id: string): Promise<{ ok: boolean }> {
+  return api.delete<{ ok: boolean }>(`${API_BASE}/admin/schedules/${id}`)
+}
+
+export async function runScheduleNow(id: string): Promise<{ ok: boolean; message: string }> {
+  return api.post<{ ok: boolean; message: string }>(`${API_BASE}/admin/schedules/${id}/run`)
+}