Known for opulent dining rooms and chic bistros from Hong Kong to Palm Beach, 71-year-old Daniel Boulud has overseen his eponymous flagship on the Upper East Side of Manhattan — site of THR ‘s New York issue party — for over 30 years. As he prepares to open his 25th restaurant — Brasserie Boulud across from Lincoln Center — he takes stock of the new power dining in New York. How h as the formality of fine dining changed in the past 30 years? The OG restaurants are all less stuffy now; the approach is more casual and more global. The dressed-down code has evolved, which I think has contributed to the rise of private clubs. At my steakhouse, La Tete d’Or, we don’t have set rules, but 80 percent of the guests are properly attired. Those who prefer a more casual experience tend to gravitate toward the bar. W hat trends are you noticing these days in what people are eating or drinking? People are putting caviar on everything lately; it seems to be all over social media these days.…