refactor(cli): use optionalArg("id") for team get positional validator

cobra.MaximumNArgs(1) was the only direct cobra-validator use in the cli
package. The optionalArg helper is the project idiom for an optional
positional that has a flag alternative (its doc comment describes exactly
this case), and it yields the consistent "expects at most one id" error
instead of cobra's default terse message.

Author: ysyneu

internal/cli/team.go

@@ -105,7 +105,7 @@ Examples:
   flashduty team get --name "SRE Team"
   flashduty team get --ref-id "hr-dept-42"
   flashduty team get --id 123 --json`, "Teams", "ReadInfo"),
-		Args: cobra.MaximumNArgs(1),
+		Args: optionalArg("id"),
 		PreRunE: func(cmd *cobra.Command, args []string) error {
 			if len(args) == 1 {
 				return nil