Add a chart to the timeline page

[graphieros]

Requirements:

• add a line chart in a sticky block above the timeline
• 2 series, each on a separate scale (or 2 chart instances with shared selected index):

1. total size
2. dependency count

• (splines, with e18e vertical signature gradient on the path)
• interaction with timeline items is reflected on the chart (selected datapoint)

Nice to have:

• positive / negative events as markers