Order primitives — buy/sell/order

act:
  when crossover(fast, slow) and not position.is_long:
    enter long with wnav 5pct
    tag "Trend entry"
  when crossunder(fast, slow) and position.is_long:
    close long tag "Exit"

  when breakout and not position.is_hold:
    qty = position_size(1pct, atr(market.high, market.low, market.close, 14) * 2)
    enter long with size qty
    tag "risk sized"

• Story (v2, khuyến nghị): enter long|short with wnav … (% NAV), enter long|short with size … (KL/HĐ cố định), close long|short|all, flatten all.
• Alias story: enter buy ≡ enter long · enter sell ≡ enter short · close buy ≡ close long · close sell ≡ close short.
• with wnav → runtime weight: · with size → runtime qty: (nếu size mang đơn vị pct/bps → weight:).
• Legacy with size = … vẫn compile (cảnh báo) — cấm codegen mới.
• Legacy / alias callable buy(...) / long(...) / sell(...) / short(...) / order(...) — engine chấp nhận; codegen mới không dùng trừ khi user yêu cầu truyền thống.
• long(...) ≡ buy(...) · short(...) ≡ sell(...).
• Chỉ trong block act: / signals:. Allocator: quanta score … (xem stmt/signal) — trong hoặc ngoài when.

Tham số order (runtime)

• Nhóm synonym: long = buy() = enter long = enter buy = close short = close sell.
• Nhóm synonym: short = sell() = enter short = enter sell = close long = close buy.