feat(dashboard): add company filter — switch between portfolio overview and single company view

frontend/src/components/dashboard/HealthHeatmap.tsx

@@ -155,16 +155,19 @@ export function HealthTrends({ companyId }: { companyId?: string }) {
     </div>
   );
 }
-export function HealthHeatmap() {
+export function HealthHeatmap({ companyId }: { companyId?: string }) {
   const [data, setData] = useState<HeatmapRow[]>([]);
   const [loading, setLoading] = useState(true);
 
   useEffect(() => {
     apiFetch<HeatmapRow[]>("/dashboard/heatmap")
-      .then((res) => setData((res.data as HeatmapRow[]) || []))
+      .then((res) => {
+        const rows = (res.data as HeatmapRow[]) || [];
+        setData(companyId ? rows.filter((r) => r.company_id === companyId) : rows);
+      })
       .catch(() => {})
       .finally(() => setLoading(false));
-  }, []);
+  }, [companyId]);
 
   if (loading) return <LoadingSpinner />;
   if (!data.length) return <EmptyState title="暂无热力图数据" />;