President Obama’s surprise declaration Friday granting temporary residency to illegal immigrants who came here as children uncorked a wave of celebration among young immigrants across Massachusetts, coming just days after another gloomy high-school graduation season ended without resolution of one of the immigration debate’s most poignant and contentious issues. The Obama administration granted immigrants brought here before age 16 the right to apply for deferred action, meaning they will not be deported and can apply for work permits.