修复：领券单券成功率按任务独立统计

app/models/__init__.py

@@ -21,6 +21,7 @@ from app.models.cps_wx_user import CpsWxUser  # noqa: F401
 from app.models.comparison_milestone import ComparisonMilestoneClaim  # noqa: F401
 from app.models.device import DeviceLiveness  # noqa: F401
 from app.models.coupon_state import (  # noqa: F401
+    CouponClaimEvent,
     CouponClaimRecord,
     CouponDailyCompletion,
     CouponPromptEngagement,

app/models/coupon_state.py

@@ -96,6 +96,40 @@ class CouponClaimRecord(Base):
         )
 
 
+class CouponClaimEvent(Base):
+    """一次领券任务中的单券结果，按 ``(trace_id, coupon_id)`` 幂等。"""
+
+    __tablename__ = "coupon_claim_event"
+    __table_args__ = (
+        UniqueConstraint(
+            "trace_id", "coupon_id",
+            name="uq_coupon_claim_event_trace_coupon",
+        ),
+        Index("ix_coupon_claim_event_date_env", "claim_date", "app_env"),
+    )
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    trace_id: Mapped[str] = mapped_column(String(64), nullable=False, index=True)
+    device_id: Mapped[str] = mapped_column(String(64), nullable=False)
+    user_id: Mapped[int | None] = mapped_column(Integer, index=True, nullable=True)
+    coupon_id: Mapped[str] = mapped_column(String(64), nullable=False)
+    claim_date: Mapped[date] = mapped_column(Date, nullable=False)
+    status: Mapped[str] = mapped_column(String(24), nullable=False)
+    app_env: Mapped[str | None] = mapped_column(String(16), index=True, nullable=True)
+    vendor: Mapped[str | None] = mapped_column(String(48), nullable=True)
+    coupon_name: Mapped[str | None] = mapped_column(String(128), nullable=True)
+    claimed_count: Mapped[int | None] = mapped_column(Integer, nullable=True)
+    reason: Mapped[str | None] = mapped_column(String(255), nullable=True)
+    extra: Mapped[dict | None] = mapped_column(_JSON, nullable=True)
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), server_default=func.now(), nullable=False
+    )
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), server_default=func.now(), onupdate=func.now(),
+        nullable=False,
+    )
+
+
 class CouponDailyCompletion(Base):
     """按 (device, 自然日) 记"今天是否已跑完整轮领券(到 done 帧)"——首页置灰源。