feat(coupon-data): 领券成功率看板(整单/点位/分平台 + 按券)

- coupon_session.platform_success:整单成功率②/点位成功率③ + 分平台点位成功率
- coupon_claim_record.app_env:按 coupon_id「按券成功率」聚合 + 子端点 /admin/api/coupon-data/coupons
- /step 复用 record_claims 同一 SessionLocal 写入(fire-and-forget),pricebot 转发/负载不变
- 迁移 coupon_session_platform_success + coupon_claim_app_env;新增 14 测试
- 设计见 docs/guides/领券成功率指标-设计与埋点.md

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

app/admin/routers/coupon_data.py

@@ -18,6 +18,8 @@ from app.admin.schemas.coupon_data import (
     CouponDataOut,
     CouponDataRow,
     CouponDataSummary,
+    CouponSlotRow,
+    CouponSlotsOut,
     CouponUserRecordsOut,
 )
 from app.core.rewards import cn_today
@@ -87,6 +89,35 @@ def get_coupon_data(
     )
 
 
+@router.get(
+    "/coupons",
+    response_model=CouponSlotsOut,
+    summary="按券成功率(coupon_id 粒度;成功/(成功+失败),skipped 排除,设备-天口径)",
+)
+def get_coupon_slots(
+    db: AdminDb,
+    date_from: Annotated[str | None, Query(description="起始日 北京 YYYY-MM-DD,默认今天")] = None,
+    date_to: Annotated[str | None, Query(description="结束日 北京 YYYY-MM-DD,闭区间,默认=date_from")] = None,
+    app_env: Annotated[str, Query(description="prod(默认) / dev / all(全部环境)")] = "prod",
+) -> CouponSlotsOut:
+    today = cn_today()
+    d_from = _parse_day(date_from, field="date_from", default=today)
+    d_to = _parse_day(date_to, field="date_to", default=d_from)
+    if d_to < d_from:
+        raise HTTPException(status_code=422, detail="date_to 不能早于 date_from")
+    if (d_to - d_from).days + 1 > _MAX_RANGE_DAYS:
+        raise HTTPException(status_code=422, detail=f"区间最长 {_MAX_RANGE_DAYS} 天")
+    env = None if app_env == "all" else app_env
+    result = coupon_data.coupon_slot_report(
+        db, date_from=d_from.isoformat(), date_to=d_to.isoformat(), app_env=env
+    )
+    return CouponSlotsOut(
+        date_from=d_from.isoformat(),
+        date_to=d_to.isoformat(),
+        items=[CouponSlotRow(**r) for r in result["items"]],
+    )
+
+
 @router.get(
     "/user-records",
     response_model=CouponUserRecordsOut,