CSV input (auto-detects headers). For multi-series, use columns like x, Series A,
Series B. For OHLC: Date, Open, High, Low, Close. Heatmap: first row headers,
first col row labels.
Advanced JSON (optional): an array of Plotly traces, or { traces:[], layout:{} }.
Supported types
Line, Area, Bar, Stacked Bar, Scatter, Bubble, Pie, Donut, Radar (polar), Polar Bar, Heatmap, Histogram, Box,
Violin, Candlestick, OHLC, 3D Scatter, 3D Surface.