fix(chart): show correct chart type in previews

- Use NoteChart directly with props instead of NoteChartFromCode
- Remove markdown ticks from chartSuggestionToMarkdown output
- Export NoteChart component for direct use in previews

Now the 3 suggestions correctly show different chart types.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

memento-note/components/note-chart.tsx

@@ -49,7 +49,7 @@ function useDarkMode() {
   return isDark
 }
 
-function NoteChart({ type, title, data, colors, showLegend, height = 250 }: NoteChartProps) {
+export function NoteChart({ type, title, data, colors, showLegend, height = 250 }: NoteChartProps) {
   const chartColors = colors ?? CHART_COLORS
   const dark = useDarkMode()