chore: add system metrics

backend/internal/grpcsrv/collector/services.go

@@ -36,3 +36,35 @@ func (c *Collector) ReportServices(ctx context.Context, req *proto.ServicesUpdat
 
 	return &proto.ServicesUpdateResp{}, nil
 }
+
+// ReportSystemMetrics handles system metrics update from an agent.
+// Agents send their current system metrics (CPU, RAM, disk, network).
+func (c *Collector) ReportSystemMetrics(ctx context.Context, req *proto.SystemMetrics) (*proto.SystemMetricsResp, error) {
+	md, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
+		return nil, fmt.Errorf("no metadata in context")
+	}
+
+	whoamiVals := md["whoami"]
+	if len(whoamiVals) == 0 {
+		return nil, fmt.Errorf("whoami metadata missing")
+	}
+	agentName := whoamiVals[0]
+
+	metrics := SystemMetrics{
+		CPUPercent:    req.CpuPercent,
+		MemoryPercent: req.MemoryPercent,
+		DiskPercent:   req.DiskPercent,
+		NetworkRxBytes: req.NetworkRxBytes,
+		NetworkTxBytes: req.NetworkTxBytes,
+	}
+
+	if ok := c.tracker.UpdateSystemMetrics(agentName, metrics); ok {
+		log.Printf("Updated system metrics for agent %s: CPU=%.1f%%, RAM=%.1f%%, Disk=%.1f%%",
+			agentName, metrics.CPUPercent, metrics.MemoryPercent, metrics.DiskPercent)
+	} else {
+		log.Printf("Warning: received system metrics for unknown agent %s", agentName)
+	}
+
+	return &proto.SystemMetricsResp{}, nil
+}