ux(overview): slim the System card to 3 compact rows

Drop the OS row and compact Memory/Uptime so the System card matches
the density of its sibling cards. Full detail stays on the deep system
stats page.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Signed-off-by: librelad <librelad@digitalangels.vip>

containers/libreportal/frontend/js/components/admin/admin-overview.js

@@ -149,9 +149,10 @@ class AdminOverview {
             'System',
             sysKind,
             this.line('Disk', disk.text || `${diskPct}%`)
-                + this.line('Memory', mem.text || '—')
-                + this.line('Uptime', (info.uptime || '—').replace(/^up /, ''))
-                + this.line('OS', info.os || '—'),
+                + this.line('Memory', mem.total
+                    ? `${this.gb(mem.used)} / ${this.gb(mem.total)} (${Math.round(mem.percent) || 0}%)`
+                    : (mem.text || '—'))
+                + this.line('Uptime', this.shortUptime(info.uptime)),
             `<button type="button" class="backup-secondary-btn" data-admin-go="system">View system stats →</button>`
         );
 
@@ -180,6 +181,22 @@ class AdminOverview {
         while (n >= 1024 && i < u.length - 1) { n /= 1024; i++; }
         return `${n.toFixed(i ? 1 : 0)} ${u[i]}`;
     }
+
+    // Compact gigabytes, e.g. 2030043136 → "1.9G", matching the Disk row's style.
+    gb(n) {
+        return `${((parseInt(n) || 0) / 1073741824).toFixed(1)}G`;
+    }
+
+    // "up 1 hour, 11 minutes" → "1h 11m".
+    shortUptime(u) {
+        return (u || '—')
+            .replace(/^up\s+/, '')
+            .replace(/\s*weeks?/g, 'w')
+            .replace(/\s*days?/g, 'd')
+            .replace(/\s*hours?/g, 'h')
+            .replace(/\s*minutes?/g, 'm')
+            .replace(/,/g, '');
+    }
 }
 
 window.AdminOverview = AdminOverview;