Remove dashboard health top-level navigation (#123)

apps/dashboard/src/SystemStatusStrip.tsx

@@ -0,0 +1,66 @@
+import type { DashboardOverview } from './api';
+import type { Messages } from './i18n';
+
+type HealthLevel = 'stale' | 'down';
+type ServiceRow = DashboardOverview['services'][number];
+
+export interface SystemStatusStripProps {
+  overview: DashboardOverview;
+  t: Messages;
+}
+
+const HEALTH_STALE_MS = 5 * 60_000;
+const HEALTH_DOWN_MS = 15 * 60_000;
+
+function serviceAgeMs(service: ServiceRow, generatedAt: string): number | null {
+  const updated = new Date(service.updatedAt).getTime();
+  const now = new Date(generatedAt).getTime();
+  if (Number.isNaN(updated) || Number.isNaN(now)) return null;
+  return Math.max(0, now - updated);
+}
+
+function serviceHealthLevel(
+  service: ServiceRow,
+  generatedAt: string,
+): HealthLevel | null {
+  const age = serviceAgeMs(service, generatedAt);
+  if (age === null) return 'stale';
+  if (age >= HEALTH_DOWN_MS) return 'down';
+  if (age >= HEALTH_STALE_MS) return 'stale';
+  return null;
+}
+
+export function SystemStatusStrip({ overview, t }: SystemStatusStripProps) {
+  const serviceLevels = overview.services.map((service) =>
+    serviceHealthLevel(service, overview.generatedAt),
+  );
+  const down = serviceLevels.filter((level) => level === 'down').length;
+  const stale = serviceLevels.filter((level) => level === 'stale').length;
+  const ciPaused = overview.tasks.watchers.paused;
+  const hasNoHeartbeat = overview.services.length === 0;
+  const level: HealthLevel = hasNoHeartbeat || down > 0 ? 'down' : 'stale';
+
+  if (!hasNoHeartbeat && down === 0 && stale === 0 && ciPaused === 0) {
+    return null;
+  }
+
+  const signals: string[] = [];
+  if (hasNoHeartbeat) signals.push(t.service.empty);
+  if (down > 0) signals.push(`${down} ${t.health.levels.down}`);
+  if (stale > 0) signals.push(`${stale} ${t.health.stale}`);
+  if (ciPaused > 0) signals.push(`${ciPaused} ${t.health.ciFailures}`);
+
+  return (
+    <aside
+      aria-label={t.health.signals}
+      className={`system-status-strip system-status-${level}`}
+      role="status"
+    >
+      <div>
+        <span className="eyebrow">{t.health.system}</span>
+        <strong>{t.health.levels[level]}</strong>
+      </div>
+      <p>{signals.join(' · ')}</p>
+    </aside>
+  );
+}