refactor(usage): modularize UsagePage into separate section components

src/components/usage/ModelStatsCard.tsx

@@ -0,0 +1,54 @@
+import { useTranslation } from 'react-i18next';
+import { Card } from '@/components/ui/Card';
+import { formatTokensInMillions, formatUsd } from '@/utils/usage';
+import styles from '@/pages/UsagePage.module.scss';
+
+export interface ModelStat {
+  model: string;
+  requests: number;
+  tokens: number;
+  cost: number;
+}
+
+export interface ModelStatsCardProps {
+  modelStats: ModelStat[];
+  loading: boolean;
+  hasPrices: boolean;
+}
+
+export function ModelStatsCard({ modelStats, loading, hasPrices }: ModelStatsCardProps) {
+  const { t } = useTranslation();
+
+  return (
+    <Card title={t('usage_stats.models')}>
+      {loading ? (
+        <div className={styles.hint}>{t('common.loading')}</div>
+      ) : modelStats.length > 0 ? (
+        <div className={styles.tableWrapper}>
+          <table className={styles.table}>
+            <thead>
+              <tr>
+                <th>{t('usage_stats.model_name')}</th>
+                <th>{t('usage_stats.requests_count')}</th>
+                <th>{t('usage_stats.tokens_count')}</th>
+                {hasPrices && <th>{t('usage_stats.total_cost')}</th>}
+              </tr>
+            </thead>
+            <tbody>
+              {modelStats.map((stat) => (
+                <tr key={stat.model}>
+                  <td className={styles.modelCell}>{stat.model}</td>
+                  <td>{stat.requests.toLocaleString()}</td>
+                  <td>{formatTokensInMillions(stat.tokens)}</td>
+                  {hasPrices && <td>{stat.cost > 0 ? formatUsd(stat.cost) : '--'}</td>}
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        </div>
+      ) : (
+        <div className={styles.hint}>{t('usage_stats.no_data')}</div>
+      )}
+    </Card>
+  );
+}