feat: add operational Dashboard

backend/app/frontend/static/app.css

@@ -1489,3 +1489,132 @@ button.map-position:hover {
     .repair-search, .repair-filter-actions { grid-column: auto; }
     .repair-table td { grid-template-columns: 90px minmax(0, 1fr); }
 }
+
+/* Dashboard */
+.dashboard-status-band {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 16px;
+    margin-bottom: 12px;
+}
+
+.dashboard-status-band p { margin: 0; }
+.dashboard-permission-note { color: var(--muted); font-size: 12px; }
+
+.dashboard-grid {
+    display: grid;
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+    gap: 12px;
+}
+
+.dashboard-section {
+    min-width: 0;
+    border: 1px solid var(--line);
+    border-radius: 6px;
+    padding: 16px;
+    background: var(--surface);
+}
+
+.dashboard-section-head {
+    display: flex;
+    align-items: flex-start;
+    justify-content: space-between;
+    gap: 16px;
+    margin-bottom: 12px;
+}
+
+.dashboard-section-head .eyebrow { margin: 0 0 3px; }
+.dashboard-section h2 { margin: 0; font-size: 19px; }
+.dashboard-section h3 { margin: 0 0 8px; font-size: 14px; }
+.dashboard-section .object-link { white-space: nowrap; }
+
+.dashboard-total {
+    display: flex;
+    align-items: baseline;
+    justify-content: space-between;
+    gap: 16px;
+    border-left: 4px solid var(--accent);
+    padding: 9px 11px;
+    background: #f6f8fa;
+}
+
+.dashboard-total span { color: var(--muted); font-weight: 700; }
+.dashboard-total strong { font-size: 25px; }
+
+.dashboard-dimension-grid {
+    display: grid;
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+    gap: 18px;
+    margin-top: 16px;
+}
+
+.dashboard-count-list,
+.dashboard-status-list {
+    display: grid;
+    gap: 0;
+    margin: 0;
+}
+
+.dashboard-count-list > div,
+.dashboard-status-list > div {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 12px;
+    min-height: 36px;
+    border-top: 1px solid #e3e7eb;
+}
+
+.dashboard-count-list dt,
+.dashboard-status-list dt { color: #40505f; }
+.dashboard-count-list dd,
+.dashboard-status-list dd { margin: 0; font-weight: 800; }
+.dashboard-status-list { margin-top: 10px; }
+.dashboard-status-list a { font-weight: 700; }
+.dashboard-boundary { margin: 13px 0 0; color: var(--muted); font-size: 12px; }
+
+.attention-list { display: grid; gap: 7px; }
+.attention-list a {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 12px;
+    min-height: 42px;
+    border: 1px solid var(--line);
+    border-left-width: 4px;
+    border-radius: 5px;
+    padding: 8px 11px;
+    background: #fff;
+    text-decoration: none;
+}
+
+.attention-list a[data-state="offline"] { border-left-color: var(--danger); }
+.attention-list a[data-state="unknown"] { border-left-color: #596675; }
+.attention-list a[data-state="unstable"] { border-left-color: var(--warn); }
+.attention-list a[data-state="repair"] { border-left-color: #6b4ca5; }
+.attention-list span { font-weight: 750; }
+.attention-list strong { font-size: 18px; }
+
+.dashboard-location-counts {
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+    column-gap: 18px;
+}
+
+@media (max-width: 900px) {
+    .dashboard-grid { grid-template-columns: 1fr; }
+}
+
+@media (max-width: 560px) {
+    .dashboard-status-band,
+    .dashboard-section-head { align-items: flex-start; flex-direction: column; }
+    .dashboard-dimension-grid { grid-template-columns: 1fr; }
+    .dashboard-location-counts { grid-template-columns: 1fr; }
+    .dashboard-section { padding: 13px; }
+    .dashboard-section .object-link { white-space: normal; }
+}
+
+@media (prefers-reduced-motion: reduce) {
+    .dashboard-section *,
+    .attention-list * { scroll-behavior: auto; }
+}