ax(node): replace prose comments with usage examples on Controller

Controller type and sendRequest had comments that restated the type
signature in prose. RFC-025 §2: if a comment restates what the type
signature says, delete it; show a concrete call instead.

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

pkg/node/controller.go

@@ -10,7 +10,9 @@ import (
 	"forge.lthn.ai/Snider/Mining/pkg/logging"
 )
 
-// Controller manages remote peer operations from a controller node.
+// ctrl := node.NewController(nodeManager, peerRegistry, transport)
+// rtt, _ := ctrl.PingPeer("abc123def456")
+// stats, _ := ctrl.GetRemoteStats("abc123def456")
 type Controller struct {
 	node      *NodeManager
 	peers     *PeerRegistry
@@ -59,7 +61,8 @@ func (c *Controller) handleResponse(conn *PeerConnection, msg *Message) {
 	}
 }
 
-// sendRequest sends a message and waits for a response.
+// resp, err := c.sendRequest("abc123def456", msg, 10*time.Second)
+// if err != nil { return nil, err }
 func (c *Controller) sendRequest(peerID string, msg *Message, timeout time.Duration) (*Message, error) {
 	actualPeerID := peerID