feat: add custom React trade markers for KLine chart

[tonichiga]

feat: add custom React trade markers for KLine chart

Summary

This PR adds support for rendering trade markers with a custom React component in react-native-kline-view.

Instead of only drawing native marker dots, consumers can now provide tradeComponent(trade, count) and fully control the marker UI.

What changed

• Added JS wrapper component in index.js to:
  • Accept tradeComponent prop
  • Enable native custom marker mode via useCustomTradeMarker
  • Receive marker layout events via onTradeMarkersLayout
  • Render marker overlays in React with absolute positioning and pointerEvents="none"
• Updated TypeScript types in index.d.ts:
  • Added TTrade
  • Added tradeComponent?: (trade: TTrade, count: number) => ReactNode
  • Updated default export type to functional component signature
• iOS native updates:
  • Added useCustomTradeMarker and onTradeMarkersLayout to config/bridge
  • Emitted visible marker positions from HTKLineView (debounced)
  • Disabled default native trade marker drawing in custom mode
  • Exported new view props in RNKLineView.m
• Android gradle repository remains on mavenCentral().

New feature

Custom trade marker rendering

You can now render trade markers using your own React UI.

trade payload shape:

• id: string
• timestamp: number
• price: number
• type: "buy" | "sell"

count is provided as the second argument.

Screenshot

Notes

• Marker overlay rendering is non-interactive (pointerEvents="none") to preserve chart gestures.
• iOS marker layout emission is debounced to reduce event pressure during scroll and redraw.

Testing checklist

• iOS: custom markers appear at expected candle positions
• iOS: chart pan/zoom/long-press still work with overlays
• iOS: disabling tradeComponent falls back to native markers
• TypeScript: tradeComponent prop and TTrade type are available
• Android: no regression in build and chart rendering