fix: refcount StatsCache keys, keep registrations across config change, and tidy GPU/usage render paths

src/actions/gpu-graph.ts

@@ -87,7 +87,7 @@ export class GpuGraph extends SingletonAction<GpuSettings> {
       const combined = combineSeries(histories, metric);
       value = combined.value;
       history = combined.history;
-      gpuName = `GPU ${ids.join("+")}`;
+      gpuName = ids.length > 0 ? `GPU ${ids.join("+")}` : "NO GPUS";
     } else {
       const gpuId = state.settings.gpuId ?? "all";
       value = poller?.getValue(gpuId, metric);
@@ -108,9 +108,6 @@ export class GpuGraph extends SingletonAction<GpuSettings> {
 }
 
 function parseCombo(raw: string | undefined): string[] | undefined {
-  const ids = (raw ?? "")
-    .split(",")
-    .map((s) => s.trim())
-    .filter(Boolean);
+  const ids = [...new Set((raw ?? "").split(",").map((s) => s.trim()).filter(Boolean))];
   return ids.length > 0 ? ids : undefined;
 }