Fix health tab: node identity indicator + cluster card overflow

Add node_id to metrics snapshot so the health tab shows which instance
the user is viewing from. Hoist nodeID computation so it works on both
SQLite and Postgres deployments. Fix cluster node card overflow with
text-overflow ellipsis and proper flex constraints.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/main.go

@@ -201,15 +201,18 @@ func main() {
 	// ── WebSocket Hub ─────────────────────────
 	hub := events.NewHub(bus, middleware.GetAllowedOrigins(cfg))
 
+	// ── Node Identity ────────────────
+	// Used by cluster registry (PG) and metrics endpoint (all deployments).
+	nodeID := cfg.ClusterNodeID
+	if nodeID == "" {
+		hostname, _ := os.Hostname()
+		nodeID = fmt.Sprintf("%s-%d", hostname, os.Getpid())
+	}
+
 	// ── Cluster Registry ────────────
 	// PG-backed node self-registration + heartbeat. No-op on SQLite.
 	var clusterReg *cluster.Registry
 	if database.IsPostgres() && stores.Cluster != nil {
-		nodeID := cfg.ClusterNodeID
-		if nodeID == "" {
-			hostname, _ := os.Hostname()
-			nodeID = fmt.Sprintf("%s-%d", hostname, os.Getpid())
-		}
 		clusterReg = cluster.NewRegistry(nodeID, cfg.ClusterEndpoint, stores.Cluster, hub, cluster.RegistryConfig{
 			HeartbeatInterval: cfg.ClusterHeartbeatInterval,
 			StaleThreshold:    cfg.ClusterStaleThreshold,
@@ -811,7 +814,7 @@ func main() {
 
 			// ── Metrics ─────────────────
 			metricsCollector := metrics.NewCollector(
-				database.DB, hub, bus, stores,
+				nodeID, database.DB, hub, bus, stores,
 				sandbox.SandboxStats,
 				triggerEngine.FireCount,
 				startTime,