ax(node): rename mu to mutex in NodeManager for AX Principle 1 compliance

Short name `mu` requires context to decode; `mutex` is self-describing.

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

pkg/node/identity.go

@@ -76,7 +76,7 @@ type NodeManager struct {
 	keyPair    *stmf.KeyPair
 	keyPath    string // ~/.local/share/lethean-desktop/node/private.key
 	configPath string // ~/.config/lethean-desktop/node.json
-	mu         sync.RWMutex
+	mutex sync.RWMutex
 }
 
 // NewNodeManager creates a new NodeManager, loading existing identity if available.
@@ -113,16 +113,16 @@ func NewNodeManagerWithPaths(keyPath, configPath string) (*NodeManager, error) {
 
 // if nm.HasIdentity() { return nm.GetIdentity() }
 func (n *NodeManager) HasIdentity() bool {
-	n.mu.RLock()
-	defer n.mu.RUnlock()
+	n.mutex.RLock()
+	defer n.mutex.RUnlock()
 	return n.identity != nil
 }
 
 // identity := nm.GetIdentity()
 // if identity == nil { return core.E("node", "identity not initialised", nil) }
 func (n *NodeManager) GetIdentity() *NodeIdentity {
-	n.mu.RLock()
-	defer n.mu.RUnlock()
+	n.mutex.RLock()
+	defer n.mutex.RUnlock()
 	if n.identity == nil {
 		return nil
 	}
@@ -133,8 +133,8 @@ func (n *NodeManager) GetIdentity() *NodeIdentity {
 
 // if err := nm.GenerateIdentity("my-worker", RoleWorker); err != nil { return err }
 func (n *NodeManager) GenerateIdentity(name string, role NodeRole) error {
-	n.mu.Lock()
-	defer n.mu.Unlock()
+	n.mutex.Lock()
+	defer n.mutex.Unlock()
 
 	// Generate X25519 keypair using STMF
 	keyPair, err := stmf.GenerateKeyPair()
@@ -174,8 +174,8 @@ func (n *NodeManager) GenerateIdentity(name string, role NodeRole) error {
 // secret, err := nm.DeriveSharedSecret(peer.PublicKey)
 // smsg.Encrypt(msg, base64.StdEncoding.EncodeToString(secret))
 func (n *NodeManager) DeriveSharedSecret(peerPubKeyBase64 string) ([]byte, error) {
-	n.mu.RLock()
-	defer n.mu.RUnlock()
+	n.mutex.RLock()
+	defer n.mutex.RUnlock()
 
 	if n.privateKey == nil {
 		return nil, fmt.Errorf("node identity not initialized")
@@ -274,8 +274,8 @@ func (n *NodeManager) loadIdentity() error {
 
 // Delete removes the node identity and keys from disk.
 func (n *NodeManager) Delete() error {
-	n.mu.Lock()
-	defer n.mu.Unlock()
+	n.mutex.Lock()
+	defer n.mutex.Unlock()
 
 	// Remove private key
 	if err := os.Remove(n.keyPath); err != nil && !os.IsNotExist(err) {