Best Way to Store Copper Acetate Solution?
Electroless copper plating requires a copper salt solution, of course (https://en.wikipedia.org/wiki/Electroless_copper_plating), but there are many other considerations, like the reducing agent and surface preparation.
I think that storage of the homemade copper acetate solution is a minor issue in your project and a plastic container with an air-tight lid should be perfectly fine, without refrigeration, for a few years.
However, for the actual electroplating, your copper solution may not be adequately characterized. There may be excess acetic acid, other stuff from the vinegar (which could be perfectly safe to consume, but not for sensitive chemical reactions). Commercial copper salts are available inexpensively and with high purity, if the project you are working on has significant value.