Search and replace

Unless I’m missing something, Scrivener badly needs a search-and-replace by formatting. For instance, I need a way to replace plain text quote/inch marks with smart quotes and plain-text apostrophe’s with typographically correct smart marks.

Or is there a way to do this already?

There isn’t a search and replace by formatting, but the particular case you need isn’t a formatting instance; smart quotes and straight quotes are separate characters. You can use the regular find/replace to convert these or, more simply, use Format > Convert > Quotes to Smart Quotes.