feat: auto-sync full lotto history on stats api access

backend/app/db.py

@@ -88,6 +88,30 @@ def upsert_draw(row: Dict[str, Any]) -> None:
             ),
         )
 
+def upsert_many_draws(rows: List[Dict[str, Any]]) -> None:
+    data = [
+        (
+            int(r["drw_no"]), str(r["drw_date"]),
+            int(r["n1"]), int(r["n2"]), int(r["n3"]),
+            int(r["n4"]), int(r["n5"]), int(r["n6"]),
+            int(r["bonus"])
+        ) for r in rows
+    ]
+    with _conn() as conn:
+        conn.executemany(
+            """
+            INSERT INTO draws (drw_no, drw_date, n1, n2, n3, n4, n5, n6, bonus)
+            VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
+            ON CONFLICT(drw_no) DO UPDATE SET
+              drw_date=excluded.drw_date,
+              n1=excluded.n1, n2=excluded.n2, n3=excluded.n3,
+              n4=excluded.n4, n5=excluded.n5, n6=excluded.n6,
+              bonus=excluded.bonus,
+              updated_at=datetime('now')
+            """,
+            data
+        )
+
 def get_latest_draw() -> Optional[Dict[str, Any]]:
     with _conn() as conn:
         r = conn.execute("SELECT * FROM draws ORDER BY drw_no DESC LIMIT 1").fetchone()