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

AX Principle 2 — comments must show HOW with real values, not restate
what the type signature already says.

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

pkg/node/controller.go

@@ -177,7 +177,8 @@ func (c *Controller) StartRemoteMiner(peerID, minerType, profileID string, confi
 	return nil
 }
 
-// StopRemoteMiner requests a remote peer to stop a miner.
+// err := ctrl.StopRemoteMiner("abc123def456", "xmrig")
+// if err != nil { log("stop failed:", err) }
 func (c *Controller) StopRemoteMiner(peerID, minerName string) error {
 	identity := c.node.GetIdentity()
 	if identity == nil {