What should I do if I had a bicycle stolen, found it at a bike shop for sale, and it was fully repaired?

Probably not because at some point, the shop may actually be held responsible or liability for receiving stolen property.  If the shop was a bona fide purchaser for value without notice, you may be out a bicycle and would need to file suit against the thief if the shop has contact information, etc.

However, if you have received your bicycle back (via police intervention), did the police calmly convince the shop owner to relinquish the bicycle and seek funds through his or her insurance company? Did you have insurance on the bicycle? If not, do you have homeowner's insurance - it may be covered there.