fix(admin): shorten dashboard table headers

- compact CPU/Mem/Procs/Disk column titles so the table does not overflow

src/internal/admin/templates/admin_overview.html

@@ -174,10 +174,10 @@ a.copy.copied { border-color: #86efac; background: #dcfce7; color: #15803d; }
           <th>{{if eq .Lang "zh"}}状态{{else}}State{{end}}</th>
           <th>{{if eq .Lang "zh"}}端口 (SSH){{else}}Ports (SSH){{end}}</th>
           <th>{{if eq .Lang "zh"}}配额 CPU/内存/磁盘{{else}}Quota CPU/Mem/Disk{{end}}</th>
-          <th>{{if eq .Lang "zh"}}CPU 使用（近 5 分钟）{{else}}CPU use (5m avg){{end}}</th>
-          <th>{{if eq .Lang "zh"}}内存使用（最近采样）{{else}}Mem use (latest){{end}}</th>
+          <th>{{if eq .Lang "zh"}}5分钟CPU{{else}}5m CPU{{end}}</th>
+          <th>{{if eq .Lang "zh"}}内存{{else}}Mem{{end}}</th>
           <th>{{if eq .Lang "zh"}}进程{{else}}Procs{{end}}</th>
-          <th>{{if eq .Lang "zh"}}磁盘用量（最近采样）{{else}}Disk used (latest){{end}}</th>
+          <th>{{if eq .Lang "zh"}}磁盘{{else}}Disk{{end}}</th>
           <th>{{if eq .Lang "zh"}}本月流量 上/下{{else}}Bandwidth ↑/↓{{end}}</th>
           {{if .IPv6PoolMode}}<th>IPv6</th>{{end}}
           <th>{{if eq .Lang "zh"}}操作{{else}}Actions{{end}}</th>