Unify hub dashboard positions into one card with exchange links.

Co-authored-by: Cursor <cursoragent@cursor.com>

manual_trading_hub/static/dashboard.css

@@ -247,11 +247,43 @@ body.hub-page-dashboard .page#page-dashboard {
 
 .dash-ac-grid {
   display: grid;
-  grid-template-columns: repeat(auto-fit, minmax(min(100%, 280px), 1fr));
+  grid-template-columns: 1fr;
   gap: 12px;
   padding: 14px;
 }
 
+.dash-pos-unified-card {
+  width: 100%;
+}
+
+.dash-ex-link {
+  appearance: none;
+  border: 0;
+  background: transparent;
+  color: var(--dash-accent);
+  font: inherit;
+  font-weight: 600;
+  padding: 0;
+  cursor: pointer;
+  text-decoration: underline;
+  text-underline-offset: 2px;
+}
+
+.dash-ex-link:hover {
+  color: color-mix(in srgb, var(--dash-accent) 80%, #fff);
+}
+
+.dash-empty-inline {
+  padding: 8px 0 4px;
+  font-size: 0.78rem;
+}
+
+.dash-pos-alert-note {
+  margin-top: 4px;
+  font-size: 0.75rem;
+  color: var(--dash-warn);
+}
+
 .dash-ac-card {
   position: relative;
   padding: 14px 16px;