By Tom Balmforth and Pavel Polityuk KYIV (Reuters) -Ukraine on Sunday claimed full control of the eastern logistics hub of Lyman, Kyiv’s most significant battlefield gain in weeks, providing a potential staging post for further attacks to the east while heaping further pressure on the Kremlin. The stinging setback for Russian President Vladimir Putin came after he proclaimed the annexation of four regions covering nearly a fifth of Ukraine on Friday, an area that includes Lyman. Kyiv and the West have condemned the proclamation as an illegitimate farce. NATO Secretary General Jens Stoltenberg …