TEHRAN, Iran — A newly built avant-garde mosque in the heart of Iran’s capital would have hard-liners shouting from the minarets — if there were any. The architects behind the Vali-e-Asr mosque dispensed with the traditional rounded domes and towering minarets, opting instead for a modern design of undulating waves of gray stone and concrete, which they say complements the surrounding architecture and evokes the austerity of early Islam. The new structure has infuriated hard-liners, who see it as part of a creeping secular onslaught on the Islamic republic.