It’s an hour and half before Naïka is due to take the stage at Irving Plaza, plenty of time for fans to grab dinner, a drink, or enjoy the mild early spring night. Yet they’re lined up early, trailing down the street and wrapping around the block, to ensure a prime location inside. Naïka’s first tour in the U.S., “ECLESIA,”brings her unique brand of jazzy R&B-slash-pop to American audiences. Inside the venue, the vibe turns tropical.