Expression $[-1] throws ArrayIndexOutOfBoundsException on empty array input #106

Title

$[-1] throws ArrayIndexOutOfBoundsException when evaluating against an empty array []

Description

The expression $[-1] (to get the last element of an array) throws an ArrayIndexOutOfBoundsException when evaluated against an empty array [], instead of returning no match/null as expected and as seen in the official JSONata online evaluator.

Steps to Reproduce

1. Define the expression $[-1].
2. Evaluate the expression against an empty array [].

Sample Code:

import com.dashjoin.jsonata.Jsonata;
import java.util.List;

public class UnitTest {
    public static void main(String[] args) {
        var jsonata = Jsonata.jsonata("$[-1]");
        System.out.println(jsonata.evaluate(List.of()));
    }
}

Expected Behavior

The expression should return null or no match (consistent with the behavior in the official JSONata Exerciser) without throwing an exception.

Actual Behavior

The evaluation throws an ArrayIndexOutOfBoundsException:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index -1 out of bounds for length 0
	at java.base/java.util.ImmutableCollections$ListN.get(ImmutableCollections.java:687)
	at com.dashjoin.jsonata.Jsonata.evaluateFilter(Jsonata.java:503)
	at com.dashjoin.jsonata.Jsonata._evaluate(Jsonata.java:212)
	at com.dashjoin.jsonata.Jsonata.evaluate(Jsonata.java:131)
	at com.dashjoin.jsonata.Jsonata.evaluate(Jsonata.java:2583)
	at com.dashjoin.jsonata.Jsonata.evaluate(Jsonata.java:2544)
	at com.example.demo.UnitTest.main(UnitTest.java:17)