Keep continuous ladders running after unconfirmed cancels

[jackhai9]

Summary

• classify unconfirmed single-row cancellations separately from structural cancellation failures
• finish capacity release and continue the unfinished continuous close ladder without counting the unconfirmed order as cancelled
• preserve fail-closed behavior for symbol changes, invalid controls, click failures, and unresolved dialogs

Validation

• npm run build:binance-orderbook-trade
• npm test (477 passed)
• npm run check:binance-orderbook-trade
• git diff --check