Lots of great info here.
Carrots and cherry tomatoes are favourites with my kids (and visitors) because they can pull one out and eat it fresh - many other things need to be cooked first.

For true survival food, nuts and fruit trees are good, but they require a long term commitment and probably more space than you have, but dwarf varieties can be grown in large containers. Many nuts can keep in the shell for a whole year (until next harvest), and a good fruit tree or trees can produce a huge amount of seasonal produce – with say apples you can get an early, mid and late fruiting variety so you can have fruit for a long period. What you don’t eat fresh, you can store in a cold cellar, freeze, dry, make jam, make jelly and then make wine or cider from the rest.