Kitchen Large Electric Appliances - detergent powder did not dissolve during dishwasher cycle

I have a 1995 GE model#GSD530 dishwasher. I used it last night. I seemed to hear all the normal cycle, clicking, and whooshing noises while it ran. When the cycle completed and I opened it, all the undissolved detergent powder was at the bottom of the tub.

I think I know what might have happened. I have the hot water turned off at my house while I investigate a hot water leak under the concrete slab.

Is this what did it?

Does this mean my dishwasher was running on little or no water flow? When the cycle completed, I noticed moisture inside there.

Might I have caused some damage or shortened the life of the dishwasher?

Is it ok if I throw some pails of heated water in there to wash the detergent powder down the drain? Otherwise I have to wipe up the powder

Your dishwasher should only be getting water from the hot water supply line so if you have it shut off, no water getting to dishwasher. There usually is a small amount of water left in dishwasher after wash cycle from previous use so that is all that was circulated when you last used it. Not enough to wash detergent from dispenser cup. Probably didn't hurt machine but don't use it again for a whole cycle until water is turned back on. You can manually add some water to dissolve detergent. Let it wash for a few minutes & move timer by hand to get to pump-out cycle.