18: Add a codec class for Base58

src/main/tjava/com/r35157/libs/codec/Base58Codec.tjava

@@ -0,0 +1,5 @@
+package com.r35157.libs.codec;
+
+public interface Base58Codec {
+    String encode(byte[] input);
+}

src/main/tjava/com/r35157/libs/jupiter/perps/JupiterPerpsPosition.tjava

@@ -12,10 +12,12 @@ import java.math.BigDecimal;
  * @param positionAccount the Solana account address of the Jupiter Perps position
  * @param entryPrice the entry price of the position, denominated in USDC
  * @param direction whether the position is long or short
+ * @param tradedTokenMint the mint address of the token being traded
  */
 public record JupiterPerpsPosition(
         ΩJupiterPerpsPositionAccountΩ positionAccount,
         ΩUSDCPriceΩ entryPrice,
-        JupiterPerpsPositionDirection direction
+        JupiterPerpsPositionDirection direction,
+        ΩSPLMintAddressΩ tradedTokenMint
 ) {
 }