fix(P1-A/P1-B): ingest 联赛级计数修正 + 非法 cursor 400

P1-A: ingest 联赛级 inserted/updated 读 r["leagues"][code] 而非顶层 r.get("inserted");
抽 _accumulate_ingest_result 纯函数 + 合约测试(4/4)。

P1-B: 非法 cursor 不再静默忽略,返回 400 + detail.code=INVALID_CURSOR;
抽 _parse_cursor 纯函数 + 测试(8/8)。

全量 307 通过。

src/api/routes/matches.py

@@ -14,6 +14,20 @@ from src.db.models import League, Match, MatchStats, Prediction, Standing, Team
 router = APIRouter(prefix="/api/v1", tags=["data"])
 
 
+def _parse_cursor(cursor: str) -> tuple[datetime, int]:
+    """P1-B: 解析游标。非法格式 → HTTPException(400, code=INVALID_CURSOR)。"""
+    try:
+        last_date_str, last_id_str = cursor.split("|", 1)
+        last_date = datetime.fromisoformat(last_date_str)
+        last_id = int(last_id_str)
+        return last_date, last_id
+    except (ValueError, AttributeError) as e:
+        raise HTTPException(
+            status_code=400,
+            detail={"code": "INVALID_CURSOR", "message": f"非法游标格式: {cursor}(应为 date_iso|id)"},
+        ) from e
+
+
 def _stats_dict(stats) -> dict | None:
     """把 MatchStats ORM 对象序列化为前端可读的扁平 dict。"""
     if stats is None:
@@ -65,26 +79,21 @@ async def list_matches(
     )
 
     if cursor:
-        try:
-            # 用 | 分隔,避免 isoformat 含 _ 时解析失败
-            last_date_str, last_id_str = cursor.split("|", 1)
-            last_date = datetime.fromisoformat(last_date_str)
-            last_id = int(last_id_str)
-            # 游标方向必须与排序方向一致:
-            # - scheduled(ASC):取「更大」的未开赛场次
-            # - 其它(DESC):取「更小」的已赛场次
-            if status == "scheduled":
-                q = q.where(
-                    (Match.match_date > last_date) |
-                    ((Match.match_date == last_date) & (Match.id > last_id))
-                )
-            else:
-                q = q.where(
-                    (Match.match_date < last_date) |
-                    ((Match.match_date == last_date) & (Match.id < last_id))
-                )
-        except (ValueError, AttributeError):
-            pass
+        # P1-B: 解析非法 → 400 + code=INVALID_CURSOR,而非静默忽略
+        last_date, last_id = _parse_cursor(cursor)
+        # 游标方向必须与排序方向一致:
+        # - scheduled(ASC):取「更大」的未开赛场次
+        # - 其它(DESC):取「更小」的已赛场次
+        if status == "scheduled":
+            q = q.where(
+                (Match.match_date > last_date) |
+                ((Match.match_date == last_date) & (Match.id > last_id))
+            )
+        else:
+            q = q.where(
+                (Match.match_date < last_date) |
+                ((Match.match_date == last_date) & (Match.id < last_id))
+            )
 
     if league:
         stmt = select(League.id).where(League.code == league)