ui: clarify ladder stop controls

[jackhai9]

Summary

• shorten the active ladder stop label for each order direction
• keep unavailable close actions in the standard disabled style while a ladder is running
• preserve the inactive action tone only when that close direction has a confirmed position

Validation

• npm test (351/351)
• npm run test:ui (56/56)
• npm run build:binance-orderbook-trade
• npm run check:binance-orderbook-trade
• git diff --check