feat(nofxi): K-line chart with TradingView lightweight-charts

- Candlestick chart + volume histogram
- 8 trading pairs: BTC/ETH/SOL/BNB/XRP/DOGE/ADA/AVAX
- 5 timeframes: 15m/1H/4H/1D/1W
- Real-time price & 24h change display
- Auto-refresh every 30s
- Backend: /api/klines + /api/ticker (Binance futures API)
- Dark trading terminal theme, responsive resize
- Tab switching: Chat ↔ Chart

nofxi/internal/interaction/web.go

@@ -140,6 +140,9 @@ func (w *WebServer) Start(ctx context.Context) error {
 		})
 	})
 
+	// Register kline/market data API
+	RegisterKlineRoutes(mux)
+
 	// Serve web UI static files
 	if w.webDir != "" {
 		if _, err := os.Stat(filepath.Join(w.webDir, "index.html")); err == nil {