XIAMEN, China — SM Prime Holdings Inc., one of Southeast Asia’s largest integrated property developers, is investing ₱1.5 billion to expand its flagship mainland China development with a new retail and lifestyle concept targeting younger consumers.Jeffrey C. Lim, SM Prime president, said the company is constructing the CHAO Block, a 19,403-square-meter development envisioned as a “neo-urban block” that moves away from traditional shopping mall d…