NAYPYITAW, Myanmar — In Myanmar's remote capital, President Barack Obama is confronting a nation backsliding in its pledges to enact economic and political reforms that were rewarded with U.S. sanctions relief and made the long-isolated country a darling of Obama's efforts to stake out a legacy in Asia. The optimism over Myanmar's unexpected shift from military rule has subsided as reforms slow. The country's pro-democracy hero Aung San Suu Kyi remains ineligible for next year's presidential elections because of constitutional rules designed to block her. And Myanmar's minority Rohingya Muslims face escalated attacks and…