Gate one-open-per-expiry by historical expiry_ymd across days.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/tests/test_p1_p2_rules.py

@@ -152,22 +152,23 @@ def test_one_expiry_per_day(tmp_path, monkeypatch) -> None:
     from app.models.db import Database
 
     db = Database(tmp_path / "one_exp.db")
-    day = datetime(2026, 8, 1, 12, 0, tzinfo=_SH)
+    # 日历已跨到 8.3，但 8.2 开过的 260803 仍须占用
+    day = datetime(2026, 8, 3, 0, 0, 2, tzinfo=_SH)
     with db._lock:
+        db._conn.execute(
+            """INSERT INTO groups(group_id, status, expiry_ymd, open_at_ms)
+               VALUES ('G-20260802-01','closed','260803',1)"""
+        )
         db._conn.execute(
             """INSERT INTO groups(group_id, status, expiry_ymd, open_at_ms)
                VALUES ('G-20260801-01','closed','260802',1)"""
         )
-        db._conn.execute(
-            """INSERT INTO groups(group_id, status, expiry_ymd, open_at_ms)
-               VALUES ('G-20260731-01','closed','260801',1)"""
-        )
         db._conn.commit()
     used = used_expiry_ymds_for_day(db, day)
-    assert used == {"260802"}
-    assert expiry_blocked_by_one_per_day("260802", used, enabled=True) is True
-    assert expiry_blocked_by_one_per_day("260803", used, enabled=True) is False
-    assert expiry_blocked_by_one_per_day("260802", used, enabled=False) is False
+    assert used == {"260803", "260802"}
+    assert expiry_blocked_by_one_per_day("260803", used, enabled=True) is True
+    assert expiry_blocked_by_one_per_day("260804", used, enabled=True) is False
+    assert expiry_blocked_by_one_per_day("260803", used, enabled=False) is False
     db.close()