v1.1.1 - Fix overlay glucose value mismatch

Bug Fix

• Fixed overlay showing stale glucose value instead of latest reading. GetCurrentReadingAsync() used FirstOrDefault() on the ascending-sorted cached readings list, returning the oldest reading in the 10-minute window instead of the newest. Changed to LastOrDefault() so the overlay value always matches the graph window.

Full Changelog: v1.1.0...v1.1.1