# Backend Design: ECR-041 Banner Write

| Field | Value |
|-------|-------|
| ID | BD-2026-041 |
| Status | **Approved** |
| Coding | **Authorized · Implemented · Closed with ECR-041** |
| Level | L2 |
| Migration | `000051_ops_banner_write` |

## Backend Change Boundary

```text
Domain: Banner (write + C-end read)
App: AdminHandler / HomeHandler → admin.Service / home → AdminRepo
API:
  POST /api/v1/admin/cms/banners
  PUT  /api/v1/admin/cms/banners/{id}
  GET  /api/v1/home/banners?placement=home
Permission: admin.cms.write (additive); keep admin.cms.read
Audit: admin_audit_logs on POST/PUT
Table: reuse ops_banners (ECR-024)
```

## Out of boundary

FeedSlot 写 · ScheduledPublication 写 · UGC · 真支付 · soft-delete · Crisis/Handoff/ContentSafety 写 · 新 RBAC 子系统

## Rollback

1. migration down（撤权限种子）  
2. 移除写路由与 C 端读取路由  
3. H5 回退静态 `homeFeeds`  

## Refs

Spec `ops-banner-write.md` · ECR-041 · WRITE_WAVE_AUTHORIZATION · predecessor BD-2026-024