fix(tui): clip overflowing content to keep footer pinned

Sites table with many rows exceeded the fixed content height,
pushing footer down. MaxHeight now clips content that overflows
while Height still pads shorter content upward.

internal/tui/view_dashboard.go

@@ -185,7 +185,7 @@ func (m Model) viewDashboard() string {
 	if contentHeight < 1 {
 		contentHeight = 1
 	}
-	paddedContent := lipgloss.NewStyle().Height(contentHeight).Render(content)
+	paddedContent := lipgloss.NewStyle().Height(contentHeight).MaxHeight(contentHeight).Render(content)
 
 	return outerPad.Render(lipgloss.JoinVertical(lipgloss.Top, header, paddedContent, footer))
 }