Coalesce ladder submit chart saves

[jackhai9]

Summary

• capture only script-owned TradingView order-line save bursts during continuous ladder rounds
• persist one cumulative submit snapshot per round while keeping remove bursts and unrelated saves independent
• bound capture ownership, preserve foreign save wrappers, and expose live coalescing stats

Validation

• npm test (511 passed)
• npm run build:binance-orderbook-trade
• npm run check:binance-orderbook-trade
• node --check scripts/binance-orderbook-trade.user.js
• git diff --check