Three songs, summer-themed, on or very near the solstice. A respite, a celebration, a salute to whatever shreds of sanity, shoots of hope and shards of joy  we may be able to cultivate in a world that often seems hellbent, for rather baffling reasons, on denying them all. Welcome to the Sixth Annual Songs of Summer! If you’re new to this space and wondering why so-and-such song isn’t in the lineup, it may well have already had its moment in the sun, sun, sun, either here or here or here or here or here. (Those will take you to years one through five…