Fix ladder action button readiness race

[jackhai9]

Summary

• wait for the current native Binance action button to remain connected, visible, and enabled across consecutive frames
• re-resolve the semantic action button before every ladder submission
• distinguish missing-render and disabled-button failures
• cover delayed rendering, React replacement, and persistent disabled states

Validation

• npm test (380 passed)
• npm run build:binance-orderbook-trade
• npm run check:binance-orderbook-trade
• git diff --check
• live Binance DOM probe for OPEN/CLOSE transition without submitting an order