Respond to questions about school buffer zone

User should be able to ask app about the school buffer zone associated with an address. Not all addresses have a buffer zone, so we will need to handle addresses that do not have one.

Start by reading the issue and locating the app's existing address-handling and school buffer zone logic. The work is done when users can ask about the buffer zone for an address and receive an appropriate response both when a zone exists and when it does not.

Written by the indexing model from the issue text.