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/handlers/admin_metrics_test.go

@@ -28,6 +28,7 @@ func TestMetrics_SQLiteShape(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 
 	collector := metrics.NewCollector(
+		"test-node",
 		nil, // no DB
 		&mockHub{count: 5},
 		&mockBus{pub: 10, del: 20},
@@ -54,6 +55,11 @@ func TestMetrics_SQLiteShape(t *testing.T) {
 		t.Fatalf("unmarshal: %v", err)
 	}
 
+	// Node ID
+	if snap.NodeID != "test-node" {
+		t.Errorf("node_id = %q, want %q", snap.NodeID, "test-node")
+	}
+
 	// Runtime
 	if snap.Runtime.WSClients != 5 {
 		t.Errorf("ws_clients = %d, want 5", snap.Runtime.WSClients)
@@ -103,6 +109,7 @@ func TestMetrics_WithCluster(t *testing.T) {
 	}
 
 	collector := metrics.NewCollector(
+		"test-node",
 		nil,
 		&mockHub{count: 3},
 		&mockBus{},
@@ -147,6 +154,7 @@ func TestMetrics_ExtensionCounters(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 
 	collector := metrics.NewCollector(
+		"test-node",
 		nil,
 		&mockHub{},
 		&mockBus{pub: 100, del: 500},

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,

server/metrics/collector.go

@@ -18,6 +18,7 @@ import (
 
 // Snapshot is the top-level JSON response from GET /api/v1/admin/metrics.
 type Snapshot struct {
+	NodeID     string            `json:"node_id"`
 	Runtime    RuntimeMetrics    `json:"runtime"`
 	DB         DBMetrics         `json:"db"`
 	Cluster    *ClusterMetrics   `json:"cluster,omitempty"`
@@ -91,6 +92,7 @@ type TriggerFireCountFunc func() int64
 
 // Collector gathers metrics on demand for the admin endpoint.
 type Collector struct {
+	nodeID           string
 	db               *sql.DB
 	hub              ConnCounter
 	bus              BusCounter
@@ -101,8 +103,9 @@ type Collector struct {
 }
 
 // NewCollector creates a metrics collector with all required dependencies.
-func NewCollector(db *sql.DB, hub ConnCounter, bus BusCounter, stores store.Stores, sandboxFn SandboxStatsFunc, triggerFn TriggerFireCountFunc, startTime time.Time) *Collector {
+func NewCollector(nodeID string, db *sql.DB, hub ConnCounter, bus BusCounter, stores store.Stores, sandboxFn SandboxStatsFunc, triggerFn TriggerFireCountFunc, startTime time.Time) *Collector {
 	return &Collector{
+		nodeID:           nodeID,
 		db:               db,
 		hub:              hub,
 		bus:              bus,
@@ -115,7 +118,7 @@ func NewCollector(db *sql.DB, hub ConnCounter, bus BusCounter, stores store.Stor
 
 // Collect gathers all metrics synchronously and returns a snapshot.
 func (c *Collector) Collect(ctx context.Context) *Snapshot {
-	snap := &Snapshot{}
+	snap := &Snapshot{NodeID: c.nodeID}
 	snap.Runtime = c.collectRuntime()
 	snap.DB = c.collectDB(ctx)
 	snap.Cluster = c.collectCluster(ctx)

src/js/sw/surfaces/admin/health.js

@@ -121,13 +121,13 @@ function NodeCard({ node }) {
     const ageColor = node.heartbeat_age_ms < 15000 ? 'var(--accent, #2a6)' : 'var(--warning, #c80)';
 
     return html`
-        <div style="border:1px solid var(--border, #ddd);border-radius:8px;padding:12px;background:var(--bg-primary, #fff);">
-            <div style="display:flex;justify-content:space-between;align-items:center;margin-bottom:8px;">
-                <strong style="font-size:13px;">${node.node_id}</strong>
-                <span style="font-size:11px;color:${ageColor};font-weight:600;">${ageLabel}</span>
+        <div style="border:1px solid var(--border, #ddd);border-radius:8px;padding:12px;background:var(--bg-primary, #fff);overflow:hidden;">
+            <div style="display:flex;justify-content:space-between;align-items:center;margin-bottom:8px;gap:8px;">
+                <strong style="font-size:13px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;min-width:0;" title=${node.node_id}>${node.node_id}</strong>
+                <span style="font-size:11px;color:${ageColor};font-weight:600;flex-shrink:0;">${ageLabel}</span>
             </div>
-            ${node.endpoint && html`<div style="font-size:11px;color:var(--text-muted, #888);margin-bottom:8px;">${node.endpoint}</div>`}
-            <div style="display:grid;grid-template-columns:repeat(3,1fr);gap:6px;">
+            ${node.endpoint && html`<div style="font-size:11px;color:var(--text-muted, #888);margin-bottom:8px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;">${node.endpoint}</div>`}
+            <div style="display:grid;grid-template-columns:repeat(3,1fr);gap:6px;overflow:hidden;">
                 <${Stat} label="Uptime"      value=${formatDuration(stats.uptime_sec)} />
                 <${Stat} label="WS Clients"  value=${formatNum(stats.ws_clients)} />
                 <${Stat} label="Goroutines"  value=${formatNum(stats.goroutines)} />
@@ -188,8 +188,9 @@ export default function HealthSection() {
 
     return html`
         <div>
-            <div style="display:flex;justify-content:flex-end;align-items:center;margin-bottom:16px;gap:8px;">
-                <span style="font-size:11px;color:var(--text-muted, #888);">Refresh</span>
+            <div style="display:flex;justify-content:space-between;align-items:center;margin-bottom:16px;gap:8px;">
+                ${data.node_id && html`<span style="font-size:11px;color:var(--text-muted, #888);overflow:hidden;text-overflow:ellipsis;white-space:nowrap;min-width:0;" title=${data.node_id}>Viewing from <strong style="color:var(--text-primary, #ccc);">${data.node_id}</strong></span>`}
+                <span style="font-size:11px;color:var(--text-muted, #888);flex-shrink:0;">Refresh</span>
                 <select style="font-size:12px;padding:2px 6px;" value=${interval} onChange=${e => setInterval_(+e.target.value)}>
                     <option value="5">5s</option>
                     <option value="10">10s</option>