At the table, I bid 4♣, partner raised to 5♣, passed out.
Here are the wo hands:
As it turns out, 5♣ is a very lucky make. Presumably no one thinks that it is the right contract. What is the right contract? Imagine that you play 3NT and that the spades come in. You have 8 tricks. In 4♠, if the spades come in, you have more options for coming to ten tricks, I think. In 5♦ you have 8 trump, but you now need 11 tricks.
Bidding.
As to my 4♣ bid: That deuce of diamonds in partner's hand could have been the deuce if clubs, could it not?
I thought later that over 3♥, maybe my call is 4♥, meaning ok, we play game, you choose where. Providing that is what 4♥ means. More likely it means I have a stiff heart and an interest in slam. So, pick the game you think best and explain how to get there.

Help

Pass 1♦ 2♥ 2♠
Pass 3♥ Pass ?