To whom does the found item belong after the expiry of the legal period: to the worker who found it or to the owner of the shop? And where is it kept during the year, and is the intended year the Hijri year?

The person who picks up the money is responsible for it, not the shop owner. Accordingly, the worker keeps the found item and may dispose of it after a year of publicizing it without finding its owner. If he uses it for himself or gives it as charity, he remains accountable for it to its owner whenever the owner appears. The found item is publicized by announcing it in places where its owner is likely to see it, such as advertising newspapers and large commercial stores. The "year" intended in Islamic law is the Hijri year.