Coding a search box for Google site: search would be just about the easiest thing to do, HTML wise.
I doubt it would cost a thing. I bet there are 20 posters here who could do it left handed, and for free.
Even easier would be to just include a link to the Google site: search over on Google's site.
You update the forum code at most, what once or twice per year? Hardly Herculean.
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