feat(dashboard): add PR by distance and race comparison table

Made-with: Cursor

frontend/src/styles/global.css

@@ -135,6 +135,49 @@ a {
   font-size: var(--font-size-caption);
 }
 
+.dashboard-section {
+  margin-top: var(--space-6);
+}
+
+.dashboard-section__title {
+  margin: 0 0 var(--space-4);
+  font-size: var(--font-size-h2);
+}
+
+.dashboard-grid--pr {
+  margin-top: 0;
+}
+
+.comparison-table-wrapper {
+  overflow-x: auto;
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-md);
+  background: #fcfdff;
+}
+
+.comparison-table {
+  width: 100%;
+  border-collapse: collapse;
+  min-width: 720px;
+}
+
+.comparison-table th,
+.comparison-table td {
+  padding: var(--space-3);
+  text-align: left;
+  border-bottom: 1px solid var(--color-border);
+}
+
+.comparison-table th {
+  color: var(--color-text-muted);
+  font-size: var(--font-size-caption);
+  font-weight: 600;
+}
+
+.comparison-table tbody tr:last-child td {
+  border-bottom: none;
+}
+
 .race-lists {
   margin-top: var(--space-6);
   display: grid;