fix: restore exchange table scroll by adding flex constraints to tableWrap

The tableSection card wrapper broke the flex height chain — DataTable's
fillHeight couldn't constrain to viewport. Added .tableWrap with
flex: 1, min-height: 0, display: flex to re-establish the chain.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/pages/Dashboard/Dashboard.module.css

@@ -29,6 +29,14 @@
   color: var(--text-primary);
 }
 
+/* Table card must fill remaining height and allow DataTable to scroll internally */
+.tableWrap {
+  flex: 1;
+  min-height: 0;
+  display: flex;
+  flex-direction: column;
+}
+
 /* Status cell */
 .statusCell {
   display: flex;

ui/src/pages/Dashboard/Dashboard.tsx

@@ -251,7 +251,7 @@ export default function Dashboard({ onExchangeSelect, activeExchangeId }: Dashbo
 
   return (
     <div className={styles.content}>
-      <div className={tableStyles.tableSection}>
+      <div className={`${tableStyles.tableSection} ${styles.tableWrap}`}>
         <div className={tableStyles.tableHeader}>
           <span className={tableStyles.tableTitle}>
             {textFilter ? (