Deep blue ***t hole and liberals summarized:     The survey, conducted by Public Policy Pollingfor Democrat Justin Brannan’s city comptroller campaign, found Mamdani beating Cuomo 35 percent to 31 percent — a difference that is narrowly within the 4.1 percent margin of error.   Mamdani, a member of the state Assembly, has leveraged social media to gain attention in the crowded race, employing slickly produced videos highlighting his platform — like free bus service or