metrics: make the memory y-unit scale more flexible

system memory is in GiB. app memory is usually in MiB

dashboard/src/components/app/Graphs.vue

@@ -39,7 +39,7 @@ const networkWriteTotal = ref(0);
 const blockReadTotal = ref(0);
 const blockWriteTotal = ref(0);
 
-let systemMemory = {};
+const appMemory = app.memoryLimit || app.manifest.memoryLimit || 256*1024*1024;
 let systemCpus = {};
 let metricStream = null;
 
@@ -84,13 +84,7 @@ async function onPeriodChange() {
 }
 
 onMounted(async () => {
-  let error, result;
-  [error, result] = await systemModel.memory();
-  if (error) return console.error(error);
-
-  systemMemory = result;
-
-  [error, result] = await systemModel.cpus();
+  const [error, result] = await systemModel.cpus();
   if (error) return console.error(error);
 
   systemCpus = result;
@@ -124,12 +118,12 @@ onUnmounted(async () => {
 
       <GraphItem ref="memoryGraphItem"
         title="Memory"
-        :subtext="`RAM: ${prettyBinarySize(app.memoryLimit || 256*1024*1024)}`"
+        :subtext="`RAM: ${prettyBinarySize(app.memoryLimit || app.manifest.memoryLimit || 256*1024*1024)}`"
         :period="period"
         yscale="memory"
         :dataset-labels="['Memory']"
         :dataset-colors="['#9ad0f5']"
-        :memory="systemMemory"
+        :memory="appMemory"
         >
       </GraphItem>