refactor(usage): modularize UsagePage into separate section components

src/components/usage/UsageChart.tsx

@@ -0,0 +1,91 @@
+import { useTranslation } from 'react-i18next';
+import type { ChartOptions } from 'chart.js';
+import { Line } from 'react-chartjs-2';
+import { Card } from '@/components/ui/Card';
+import { Button } from '@/components/ui/Button';
+import type { ChartData } from '@/utils/usage';
+import { getHourChartMinWidth } from '@/utils/usage/chartConfig';
+import styles from '@/pages/UsagePage.module.scss';
+
+export interface UsageChartProps {
+  title: string;
+  period: 'hour' | 'day';
+  onPeriodChange: (period: 'hour' | 'day') => void;
+  chartData: ChartData;
+  chartOptions: ChartOptions<'line'>;
+  loading: boolean;
+  isMobile: boolean;
+  emptyText: string;
+}
+
+export function UsageChart({
+  title,
+  period,
+  onPeriodChange,
+  chartData,
+  chartOptions,
+  loading,
+  isMobile,
+  emptyText
+}: UsageChartProps) {
+  const { t } = useTranslation();
+
+  return (
+    <Card
+      title={title}
+      extra={
+        <div className={styles.periodButtons}>
+          <Button
+            variant={period === 'hour' ? 'primary' : 'secondary'}
+            size="sm"
+            onClick={() => onPeriodChange('hour')}
+          >
+            {t('usage_stats.by_hour')}
+          </Button>
+          <Button
+            variant={period === 'day' ? 'primary' : 'secondary'}
+            size="sm"
+            onClick={() => onPeriodChange('day')}
+          >
+            {t('usage_stats.by_day')}
+          </Button>
+        </div>
+      }
+    >
+      {loading ? (
+        <div className={styles.hint}>{t('common.loading')}</div>
+      ) : chartData.labels.length > 0 ? (
+        <div className={styles.chartWrapper}>
+          <div className={styles.chartLegend} aria-label="Chart legend">
+            {chartData.datasets.map((dataset, index) => (
+              <div
+                key={`${dataset.label}-${index}`}
+                className={styles.legendItem}
+                title={dataset.label}
+              >
+                <span className={styles.legendDot} style={{ backgroundColor: dataset.borderColor }} />
+                <span className={styles.legendLabel}>{dataset.label}</span>
+              </div>
+            ))}
+          </div>
+          <div className={styles.chartArea}>
+            <div className={styles.chartScroller}>
+              <div
+                className={styles.chartCanvas}
+                style={
+                  period === 'hour'
+                    ? { minWidth: getHourChartMinWidth(chartData.labels.length, isMobile) }
+                    : undefined
+                }
+              >
+                <Line data={chartData} options={chartOptions} />
+              </div>
+            </div>
+          </div>
+        </div>
+      ) : (
+        <div className={styles.hint}>{emptyText}</div>
+      )}
+    </Card>
+  );
+}