HANOI, Vietnam >> North Korean leader Kim Jong Un’s armored limousine, surrounded by his phalanx of burly bodyguards, rolled into Vietnam’s capital Tuesday ahead of a summit with President Donald Trump that’s meant to deal with perhaps the world’s biggest security challenge: Kim’s pursuit of a nuclear program that stands on the verge of viably threatening targets around the planet. ASSOCIATED PRESS North Korean leader Kim Jong Un, center, walks after arriving by train in Dong Dang, Vietnam. HANOI, Vietnam >> North Korean leader Kim Jong Un’s armored limousine, surrounded by his phalanx of burly bodyguards, rolled into Vietnam’s capital Tuesday ahead of a summit with President Donald Trump that’s meant to deal with perhaps the world’s biggest security challenge: Kim’s pursuit of a nuclear program that stands on the verge of viably threatening targets around the planet. Soldiers, police and international journalists thronged the streets outside Hanoi’s Melia Hotel where Kim was set to stay, and hundreds of eager citizens stood behind barricades hoping to see the North Korean leader. As Vietnamese, North Korean and U.S. flags fluttered in a cold drizzle, dozens of cameras flashed and some citizens screamed and used their mobile phones to capture Kim’s rock-star-like…