feat: add system metrics dashboard with resource monitoring

- Add system metrics endpoint (CPU load, memory, swap, network traffic)
- Collect metrics from /proc and /sys (no subprocess required)
- Overhaul dashboard to pull from per-subsystem models
- Remove deprecated /status/all monolithic endpoint
- Improve networkd import to handle optional priority prefix
- Fix CSS duplicate .grid-4 rule and unused dashboard imports

webui/static/style.css

@@ -465,6 +465,10 @@ body {
     grid-template-columns: repeat(3, 1fr);
 }
 
+.grid-4 {
+    grid-template-columns: repeat(4, 1fr);
+}
+
 /* Text Colors */
 .text-success {
     color: var(--success);
@@ -521,26 +525,39 @@ body {
 
 /* Stat cards */
 .stat-card {
-    background: var(--bg-card);
+    background: var(--bg-secondary);
+    border: 1px solid var(--border);
     border-radius: 8px;
     padding: 1rem 1.25rem;
+    border-top: 3px solid var(--accent);
+    transition: border-color 0.15s, box-shadow 0.15s;
+}
+
+.stat-card:hover {
+    border-color: var(--accent);
+    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.15);
 }
 
 .stat-card .label {
-    font-size: 12px;
+    font-size: 11px;
+    font-weight: 600;
+    text-transform: uppercase;
+    letter-spacing: 0.05em;
     color: var(--text-muted);
-    margin-bottom: 4px;
+    margin-bottom: 6px;
 }
 
 .stat-card .value {
-    font-size: 28px;
+    font-size: 32px;
     font-weight: 700;
+    color: var(--text-primary);
+    line-height: 1.2;
 }
 
 .stat-card .meta {
     font-size: 12px;
     color: var(--text-muted);
-    margin-top: 4px;
+    margin-top: 6px;
 }
 
 /* Status dot */
@@ -603,16 +620,30 @@ body {
 }
 
 .service-list li {
-    padding: 6px 0;
+    padding: 8px 0;
     display: flex;
     align-items: center;
-    gap: 8px;
+    gap: 10px;
+    border-bottom: 1px solid var(--border);
+}
+
+.service-list li:last-child {
+    border-bottom: none;
 }
 
 .service-list .svc-name {
     flex: 1;
 }
 
+/* Service status inline badge */
+.service-status {
+    display: inline-flex;
+    align-items: center;
+    gap: 6px;
+    font-weight: 500;
+    font-size: 14px;
+}
+
 /* Tabs */
 .tabs {
     display: flex;
@@ -827,7 +858,8 @@ body {
     }
 
     .grid-2,
-    .grid-3 {
+    .grid-3,
+    .grid-4 {
         grid-template-columns: 1fr;
     }
 }