animate mempool blocks conditional on mined block similarity

backend/src/mempool.interfaces.ts

@@ -153,6 +153,7 @@ export interface BlockExtension {
   feeRange: number[]; // fee rate percentiles
   reward: number;
   matchRate: number | null;
+  similarity?: number;
   pool: {
     id: number; // Note - This is the `unique_id`, not to mix with the auto increment `id`
     name: string;