ipn,tka: improve Tailnet Lock logs

* Refer to "tailnet-lock" instead of "network-lock" in log messages
* Log keys as `tlpub:<hex>` rather than as Go structs

Updates tailscale/corp#39455
Updates tailscale/corp#37904

Change-Id: I644407d1eda029ee11027bcc949897aa4ba52787
Signed-off-by: Alex Chan <alexc@tailscale.com>

ipn/ipnlocal/network-lock.go

@@ -44,7 +44,7 @@ import (
 
 var (
 	errMissingNetmap        = errors.New("missing netmap: verify that you are logged in")
-	errNetworkLockNotActive = errors.New("network-lock is not active")
+	errNetworkLockNotActive = errors.New("tailnet-lock is not active")
 
 	tkaCompactionDefaults = tka.CompactionOptions{
 		MinChain: 24,                  // Keep at minimum 24 AUMs since head.
@@ -806,7 +806,7 @@ func (b *LocalBackend) NetworkLockSign(nodeKey key.NodePublic, rotationPublic []
 func (b *LocalBackend) NetworkLockModify(addKeys, removeKeys []tka.Key) (err error) {
 	defer func() {
 		if err != nil {
-			err = fmt.Errorf("modify network-lock keys: %w", err)
+			err = fmt.Errorf("modify tailnet-lock keys: %w", err)
 		}
 	}()
 
@@ -1126,7 +1126,7 @@ func (b *LocalBackend) NetworkLockWrapPreauthKey(preauthKey string, tkaKey key.N
 		return "", fmt.Errorf("signing failed: %w", err)
 	}
 
-	b.logf("Generated network-lock credential signature using %s", tkaKey.Public().CLIString())
+	b.logf("Generated tailnet-lock credential signature using %s", tkaKey.Public().CLIString())
 	return fmt.Sprintf("%s--TL%s-%s", preauthKey, tkaSuffixEncoder.EncodeToString(sig.Serialize()), tkaSuffixEncoder.EncodeToString(priv)), nil
 }