perf(agent): sort top procs by RAM only, skip per-process CPUPercent

CPUPercent() on every process reads /proc/<pid>/stat for all processes,
causing ~19% CPU spike on servers with many containers. Sorting by RAM
is a single /proc read per process and much cheaper.

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

agent/main.go

@@ -245,17 +245,15 @@ func collectMetrics() (*Metricas, error) {
 		m.TCPConns = len(conns)
 	}
 
-	// Top 10 procesos por CPU (luego por RAM como desempate)
+	// Top 10 procesos por RAM (CPUPercent por proceso es muy costoso en sistemas con muchos contenedores)
 	if procs, err := process.Processes(); err == nil {
 		type pd struct {
 			pid   int32
 			name  string
-			cpu   float64
 			ramMB float64
 		}
 		var lista []pd
 		for _, p := range procs {
-			cpuPct, _ := p.CPUPercent()
 			name, _ := p.Name()
 			if name == "" {
 				continue
@@ -264,12 +262,12 @@ func collectMetrics() (*Metricas, error) {
 			if mi, err := p.MemoryInfo(); err == nil && mi != nil {
 				ramMB = round2(float64(mi.RSS) / (1024 * 1024))
 			}
-			lista = append(lista, pd{p.Pid, name, round2(cpuPct), ramMB})
+			if ramMB < 1 {
+				continue
+			}
+			lista = append(lista, pd{p.Pid, name, ramMB})
 		}
 		sort.Slice(lista, func(i, j int) bool {
-			if lista[i].cpu != lista[j].cpu {
-				return lista[i].cpu > lista[j].cpu
-			}
 			return lista[i].ramMB > lista[j].ramMB
 		})
 		limit := 10
@@ -277,7 +275,7 @@ func collectMetrics() (*Metricas, error) {
 			limit = len(lista)
 		}
 		for _, d := range lista[:limit] {
-			m.TopProcs = append(m.TopProcs, ProcesoInfo{d.pid, d.name, d.cpu, d.ramMB})
+			m.TopProcs = append(m.TopProcs, ProcesoInfo{d.pid, d.name, 0, d.ramMB})
 		}
 	}