Fix bank balance bigint decoding failure.

src/scripts/export/handlers/bank.ts

@@ -114,9 +114,13 @@ export const bank: HandlerMaker = async ({
         // Ignore decoding errors.
       }
 
-      // Try to decode as legacy Coin protobuf.
+      // Try to decode as legacy Coin protobuf, and ensure amount can be parsed
+      // as a bigint. Otherwise, ignore. The protobuf will decode (and not
+      // error) if the value is another protobuf, but `amount` will likely
+      // contain other data instead of a number. There's no way to ensure it's
+      // actually a coin protobuf, so this is the best we can do.
       try {
-        balance = Coin.decode(valueData).amount
+        balance = BigInt(Coin.decode(valueData).amount).toString()
       } catch {
         // Ignore decoding errors.
       }