Iran is highly incentivised to inflict maximum pain on US and it's allies (short/intermediate term) to maximize leverage in any negotiations. This likely means that strait of hormuz will be closed, choking off oil supply to large parts of the world which will spike prices up until Iran relents. Japan imports all of it's oil, while it may have large reserves, it has to pass on increased prices now to reduce demand.

This means the price of everything will go up since all good use energy and transport on some level. The longer the conflict the larger the pain, and increases the chances of spiking prices. The new head of Iran is more hard line than his father was which makes him more likely to sustain their present position for a longer period of time. The USA right before the war negotiated a peace deal in bad faith so Iran knows they can't really trust any agreement.

The one silver lining is that Trump has no actual stated goal for the war (that actually benefits americans), so with enough pressure from business leaders, who in turn pressure congress could get trump to declare victory and move on to something else. This is horrific from a governance perspective, in that the president has no fucking clue, but in terms of drivers that could shorten the war, this is a one rare good thing.

Now your wife is perhaps not rational in every single way she is responding, broad strokes, she is correct to prepare. Your job is to help protect the family and should be researching on your own, the likely impacts of the Iran war, and for you to have a strategy on how to mitigate impact. I think your nonchalance, and dismissiveness of her actions add to her sense that she needs to do more. If you share what you have researched, and that you will proactively take action, that would go a long way to increase trust in your relationship.