feat(stats): add stats page and pile trend

Show the stat groups on /stats, the pile trend on the dashboard card,
one switch per group in the settings, and the shared groups on the
public profile.

src/components/stats/TrendStats.jsx

@@ -0,0 +1,14 @@
+import {useTranslation} from 'react-i18next';
+import {TrendingDown} from 'lucide-react';
+
+import StatsSection from './StatsSection.jsx';
+import PileTrend from './PileTrend.jsx';
+
+export default function TrendStats({trend}) {
+    const {t} = useTranslation();
+    return (
+        <StatsSection title={t('STATS.TREND.TITLE')} icon={TrendingDown}>
+            <PileTrend trend={trend}/>
+        </StatsSection>
+    );
+}