By Stephen Farrell and Vira Labych LVIV, Ukraine (Reuters) – Bucha lies heavy on Luidmyla Nazarova’s mind these last few days, as she stacks humanitarian aid bound for the devastated Ukrainian city where, she just learned, her uncle was killed by Russian troops. A refugee herself, the 45-year-old political consultant said she fled Kyiv when the war started and on Monday was volunteering in St. George’s Cathedral in the western Ukrainian city of Lviv, unpacking truckloads of aid sent from churches around Europe and sending it on to wartorn cities in Ukraine. For a month she has worked in gloomy…