use environment variable to store R2_BUCKET

src/core/configuration/ProdConfig.ts

@@ -2,9 +2,6 @@ import { GameEnv } from "./Config";
 import { DefaultServerConfig } from "./DefaultConfig";
 
 export const prodConfig = new (class extends DefaultServerConfig {
-  r2Bucket(): string {
-    return "openfront-prod";
-  }
   numWorkers(): number {
     return 6;
   }