Move our custom fields to a BlockExtension sub object of the IEsploraApi.Block interface

frontend/src/app/interfaces/node-api.interface.ts

@@ -1,3 +1,5 @@
+import { Block, Transaction } from "./electrs.interface";
+
 export interface OptimizedMempoolStats {
   added: number;
   vbytes_per_second: number;
@@ -80,3 +82,17 @@ export interface MiningStats {
   pools: SinglePoolStats[],
 }
 
+export interface BlockExtension {
+  medianFee?: number;
+  feeRange?: number[];
+  reward?: number;
+  coinbaseTx?: Transaction;
+  matchRate?: number;
+
+  stage?: number; // Frontend only
+}
+
+export interface BlockExtended extends Block {
+  extra?: BlockExtension;
+}
+