(feat) add visualizations for backtesting

frontend/visualization/pnl.py

@@ -0,0 +1,15 @@
+import plotly.graph_objects as go
+import numpy as np
+import pandas as pd
+
+
+def get_pnl_trace(executors):
+    pnl = [e.net_pnl_quote for e in executors]
+    cum_pnl = np.cumsum(pnl)
+    return go.Scatter(
+        x=pd.to_datetime([e.close_timestamp for e in executors], unit="ms"),
+        y=cum_pnl,
+        mode='lines',
+        line=dict(color='blue', width=2, dash="dash"),
+        name='Cumulative PNL'
+    )