[Bug]: CtWildcardReference::equals does not respect isUpper

### Describe the bug

when comparing two wildcards using `equals`, they are considered equal even if one has an upper bound and the other's bound is a lower one.

### Source code you are trying to analyze/transform

```Java
irrelevant, see mre below
```

### Source code for your Spoon processing

```Java
var factory = new spoon.Launcher().createFactory();
var x = factory.createWildcardReference().setBoundingType(factory.Type().createReference(Object.class)).setUpper(false);
var y = factory.createWildcardReference().setBoundingType(factory.Type().createReference(Object.class)).setUpper(true);
System.out.println(x);
System.out.println(y);
System.out.println(x.equals(y));
System.out.println(y.equals(x));
```

### Actual output

```Java
? super java.lang.Object
? extends java.lang.Object
true
true
```

### Expected output

```Java
? super java.lang.Object
? extends java.lang.Object
false
false
```

### Spoon Version

11.1.0 (i looked through every changelog since then and found none where wildcards are mentioned)

### JVM Version

21.0.10

### What operating system are you using?

nixos unstable 26.11.20260823.56c02bc (Zokor)

Start at CtWildcardReference.equals and run the supplied Java reproducer with one wildcard using an upper bound and the other a lower bound. Done means the two comparisons return false while the printed wildcard forms remain ? super java.lang.Object and ? extends java.lang.Object.

Written by the indexing model from the issue text.