CALL FOR PROPOSALS TO THE "PPA of the Region of Eastern Macedonia and Thrace 2026-2030" IN THE PRIORITY AXIS: 6.7 "Green cities (urban regeneration, modernization of the urban transport fleet, buildings, etc.)" WITH THE TITLE "CONSTRUCTION OF A TECHNICAL BUILDING FOR TRANSFORMERS IN THE CENTER OF CHRYSOUPOLI IN THE CONTEXT OF THE UNDERGROUNDING OF AN EXISTING OVERHEAD ELECTRICITY NETWORK"