Rebrand user-visible CLI text; add legacy fallbacks for keyring, cache dir and version prefix

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

internal/cmd/wrapper/command_wrapper.go

@@ -35,7 +35,7 @@ type WrappableCommand interface {
 	BaseCommand() *base.Command
 }
 
-// CommandWrapper starts the boundary cache after the command was Run and attempts
+// CommandWrapper starts the threshold cache after the command was Run and attempts
 // to send the current persona to any running daemon.
 type CommandWrapper struct {
 	WrappableCommand
@@ -50,7 +50,7 @@ func Wrap(c func() WrappableCommand) cli.CommandFactory {
 	}
 }
 
-// Run runs the wrapped command and then attempts to start the boundary cache and send
+// Run runs the wrapped command and then attempts to start the threshold cache and send
 // the current token to it.
 func (w *CommandWrapper) Run(args []string) int {
 	// potentially intercept the token in case it isn't stored in the keyring