Pondering a trek to see the bold new musical “Soft Power” at The Curran in San Francisco? We don’t blame you, the inventive new “play with a musical” created by the A-List duo of David Henry Hwang (“M. Butterfly”) and composer Jeanine Tesori (“Fun Home”), “Soft Power” blends timely comedy, catchy songs and a heartfelt look at contemporary politics, art and culture. Heck, Hillary Clinton has a show-stopping number in it (well, OK, someone who plays Clinton, that is). But before you head off, here’s what you need to know.