feat(ad): eCPM 单位统一为分 + 新增看广告金币审计接口 (#32)

- eCPM 口径修正:getEcpm 原值是分/千次,新增 parse_ecpm_fen;parse_ecpm_yuan
  改为 ÷100 转元,因子1 阈值按元判档(100/200/400),收益换算用元
- test-grant 用客户端按 ad_session_id 上报的真实 eCPM 发奖(取不到/≤0 兜底 200)
- 新增 GET /admin/api/ad-coin-audit 只读复算对账(router/repo/schema),复用发奖公式
- 同步更新 docs/api、docs/database 的分/元口径

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: OuYingJun1024 <1034284404@qq.com>
Reviewed-on: #32
Co-authored-by: ouzhou <ouzhou@wonderable.ai>
Co-committed-by: ouzhou <ouzhou@wonderable.ai>

app/admin/main.py

@@ -13,6 +13,7 @@ from contextlib import asynccontextmanager
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 
+from app.admin.routers.ad_audit import router as ad_audit_router
 from app.admin.routers.admins import router as admins_router
 from app.admin.routers.audit import router as audit_router
 from app.admin.routers.auth import router as auth_router
@@ -86,3 +87,4 @@ admin_app.include_router(feedback_router)
 admin_app.include_router(admins_router)
 admin_app.include_router(audit_router)
 admin_app.include_router(config_router)
+admin_app.include_router(ad_audit_router)