feat(frontend): 精简状态监控默认概览

默认视图移除 CPU 使用率卡和网络速度卡，保留内存、
磁盘与进程管理作为常驻概览，以减少右侧窄栏中的重复
信息。
同时压缩 CPU/网络历史图的高度，避免在窄侧栏下撑开
布局。

packages/frontend/src/components/StatusMonitorNetworkHistoryChart.vue

@@ -259,8 +259,10 @@ onBeforeUnmount(() => {
 <style scoped>
 .network-history-chart {
   display: grid;
+  grid-template-rows: auto minmax(0, 1fr);
   gap: 8px;
   min-width: 0;
+  min-height: 0;
   height: auto;
   border-radius: 16px;
   border: 1px solid rgba(148, 163, 184, 0.08);
@@ -268,13 +270,14 @@ onBeforeUnmount(() => {
     linear-gradient(180deg, rgba(255, 255, 255, 0.035), rgba(255, 255, 255, 0.02)),
     radial-gradient(circle at top left, rgba(59, 130, 246, 0.06), transparent 62%);
   padding: 10px;
+  overflow: hidden;
 }
 
 .network-history-chart__header {
   display: flex;
   align-items: flex-start;
   justify-content: space-between;
-  gap: 10px;
+  gap: 8px;
 }
 
 .network-history-chart__subtitle {
@@ -326,8 +329,9 @@ onBeforeUnmount(() => {
 
 .network-history-chart__canvas {
   min-width: 0;
+  min-height: 0;
   width: 100%;
-  height: 108px;
+  height: 88px;
   overflow: hidden;
 }