ax(node): replace prose comment on MinerManager with usage example

AX Principle 2 — comments show HOW with real values, not prose descriptions.

Co-Authored-By: Charon <charon@lethean.io>

pkg/node/worker.go

@@ -11,8 +11,10 @@ import (
 	"github.com/adrg/xdg"
 )
 
-// MinerManager interface for the mining package integration.
-// This allows the node package to interact with mining.Manager without import cycles.
+// worker.SetMinerManager(miningManager)
+// miner, err := worker.minerManager.StartMiner("xmrig", cfg)
+// worker.minerManager.StopMiner("xmrig")
+// for _, m := range worker.minerManager.ListMiners() { ... }
 type MinerManager interface {
 	StartMiner(minerType string, config interface{}) (MinerInstance, error)
 	StopMiner(name string) error