By Grant Smith, Bloomberg markets live reporter and strategist Oil prices may have been confined to a tight range this month, but an array of signals from the physical market suggest the next move could be a break to the upside. First of all, there are the time-spreads between monthly futures contracts, which have shown a strengthening premium on prompt deliveries over the past six weeks as US driving demand climbs toward its summertime peak. The so-called flat price of crude has lagged behind, pressured by concerns over the global economy, but…