feat: add agentmon services section to infrastructure page

Label all agentmon docker-compose services with agentmon.monitor=true
and agentmon.group=agentmon so the swarm-monitor picks them up.
Adds Group field to ServiceSnapshot, probes /healthz for api/web roles,
and renders a separate "Agentmon" section below Swarm Services on the
Infrastructure page with new api and worker card renderers.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/store/postgres/stats.go

@@ -99,6 +99,48 @@ func (d *DB) GetSummary(ctx context.Context) (*Summary, error) {
 	}, nil
 }
 
+type TopTool struct {
+	Name  string `json:"name"`
+	Count int    `json:"count"`
+}
+
+func (d *DB) GetTopTools(ctx context.Context, limit int) ([]TopTool, error) {
+	if limit <= 0 {
+		limit = 10
+	}
+	now := time.Now()
+	midnight := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
+
+	q := `
+		SELECT
+			payload->'attributes'->>'name' AS tool_name,
+			COUNT(*)                        AS cnt
+		FROM events
+		WHERE type = 'span.end'
+		  AND payload->'attributes'->>'span_kind' = 'tool'
+		  AND payload->'attributes'->>'name' IS NOT NULL
+		  AND ts >= $1
+		GROUP BY tool_name
+		ORDER BY cnt DESC
+		LIMIT $2
+	`
+	rows, err := d.sql.QueryContext(ctx, q, midnight, limit)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var out []TopTool
+	for rows.Next() {
+		var t TopTool
+		if err := rows.Scan(&t.Name, &t.Count); err != nil {
+			return nil, err
+		}
+		out = append(out, t)
+	}
+	return out, rows.Err()
+}
+
 func bucketForWindow(window string) string {
 	switch window {
 	case "1h":