Add Plot

Here is the `plot_graph()` that is in char of the bars, scatter and vertical line plot items.

Also all the necessary code  for the graph to be shown.

examples/max_pain.py

@@ -12,7 +12,8 @@ from piker.brokers.deribit.api import (
 )
 import sys
 import pyqtgraph as pg
-from pyqtgraph import ScatterPlotItem
+from PyQt6 import QtCore
+from pyqtgraph import ScatterPlotItem, InfiniteLine
 from PyQt6.QtWidgets import QApplication
 
 def check_if_complete(
@@ -135,6 +136,21 @@ async def max_pain_daemon(
             )
             plot.addItem(scatter_iv)
 
+        total_intrinsic_value, max_pain = get_intrinsic_value_and_max_pain(intrinsic_values)
+
+        vertical_line = InfiniteLine(
+            pos=max_pain,
+            angle=90,
+            pen=pg.mkPen(color='yellow', width=2, style=QtCore.Qt.PenStyle.DotLine),
+            label=f'Max pain: {max_pain:,.0f}',
+            labelOpts={
+                'position': 0.8,
+                'color': 'yellow',
+                'movable': True
+            }
+        )
+        plot.addItem(vertical_line)
+
     def update_oi_by_strikes(msg: tuple):
         nonlocal oi_by_strikes
         if 'oi' == msg[0]: