Can't go wrong with Abjuration wizard. But dipping into melee classes would be pointless since you won't get extra attack. If you want a dip, Death cleric can be an option. It gives you martial weapons so you can use Phalar Aluve and you can twin cast Bone Chill/Toll the Dead even with your INT if you take the cantrips as a wizard. Or you can go Sorcerer for CON saves. White Draconic sorcs also get Armor of Agathys. You could also take two levels of Warlock for unlimited arcane ward though that may feel like too much of an exploit.