feat(trader): 科创板200股最小手数(分期项切片)—lot_size_for+matcher板块取整

科创板(688/689)最小200股1股递增(不整倍); 主板/创业/北交100整倍; 卖出不取整。
- limit.py 加 lot_size_for(symbol)
- matcher cross_order 买入取整按板块(star≥200不取整, 其余100整倍)
- routes_paper cta size=lot_size_for(symbol)
- test: 688981 买150拒/买250不取整; 主板用例不变; 63/63通过

sanguo_api/routes_paper.py

@@ -145,8 +145,10 @@ def _run_replay(db, aid, req: PaperCreateRequest):
         cls = get_strategy_class(s.name)
         if cls is None:
             continue   # 策略不可用（本机无 vnpy_ctastrategy）→ 跳过
+        from sanguo_trader.limit import lot_size_for
         cta = PaperCtaEngine(s.name, match_session=s.match_session,
-                             listing_days=s.listing_days, size=100)   # A 股 1 手=100 股
+                             listing_days=s.listing_days,
+                             size=lot_size_for(s.symbol))   # 主板 100 / 科创 200 股一手
         vt_symbol = f"{s.symbol}.{guess_exchange(s.symbol).value}"
         strat = cls(cta, s.name, vt_symbol, s.params)   # CtaTemplate(cta_engine, name, vt_symbol, setting)
         strat.trading = True   # 允许 send_order（等价 on_start）