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/commands/managedgroupscmd/managedgroups.gen.go

@@ -151,7 +151,7 @@ func (c *Command) Run(args []string) int {
 
 		case "list":
 			if c.FlagAuthMethodId == "" {
-				c.PrintCliError(errors.New("AuthMethod ID must be passed in via -auth-method-id or BOUNDARY_AUTH_METHOD_ID"))
+				c.PrintCliError(errors.New("AuthMethod ID must be passed in via -auth-method-id or THRESHOLD_AUTH_METHOD_ID"))
 				return base.CommandUserError
 			}