Update StandX API documentation and configuration

- Revised `.env.example` to reflect new API token generation process, emphasizing the use of creation date and validity days for token expiry management.
- Enhanced `auth.md` with detailed instructions for obtaining API tokens and signing transactions for both EVM and Solana wallets.
- Updated `maker-points-guide.md` to clarify the API token retrieval process and the significance of the Ed25519 private key.
- Refactored `config.ts` and `gateway.ts` to support new token expiry configuration methods and improved private key handling, including Base58 decoding.
- Improved overall documentation clarity and user guidance for new and existing users.

.env.example

@@ -14,12 +14,14 @@ STANDX_SYMBOL=BTC-USD
 # STANDX_BASE_URL=https://perps.standx.com
 # STANDX_WS_URL=wss://perps.standx.com/ws-stream/v1
 # STANDX_SESSION_ID=
-# Optional: request signing key (ed25519 private key, hex or base64)
+# Optional: request signing key (ed25519 private key, supports hex or base58 format)
 # STANDX_REQUEST_PRIVATE_KEY=
-# Token expiry timestamp (Unix seconds). When expired: cancels all orders, stops new orders.
-# If position exists, continues close/stop-loss logic. If no position/orders, enters silent mode.
-# Example: STANDX_TOKEN_EXPIRY=1737092800
-# STANDX_TOKEN_EXPIRY=
+# Token expiry configuration (recommended method: creation date + validity days)
+# Get these values when generating API token at https://standx.com/user/session
+# STANDX_TOKEN_CREATE_DATE=2025-01-15   # Token creation date (YYYY-MM-DD format)
+# STANDX_TOKEN_VALIDITY_DAYS=30         # Token validity period in days
+# Legacy method: direct expiry timestamp (Unix seconds)
+# STANDX_TOKEN_EXPIRY=1737092800
 
 # Core trading symbol and sizing
 TRADE_SYMBOL=BTCUSDT                    # Trading pair symbol