feat(tui): ntcharts sparkline with Y-axis labels and stats

Replaced streamline chart with ntcharts sparkline (block elements,
auto-scaling). Height=2, Y-axis labels (max/min ms) on the left,
Min/Avg/Max stats below. Denser and more readable than the line chart.

internal/tui/update.go

@@ -142,7 +142,7 @@ func (m *Model) handleFormMsg(msg tea.Msg) (tea.Model, tea.Cmd) {
 	return m, nil
 }
 
-const detailInlineHeight = 12
+const detailInlineHeight = 10
 
 func (m *Model) recalcLayout() {
 	chrome := chromeBase