feat: harden trading SDK examples

examples/wsol_wrapper/README.md

@@ -0,0 +1,13 @@
+# SOL / WSOL Operations
+
+[中文](README_CN.md)
+
+Demonstrates wrapping SOL, partially unwrapping WSOL through the SDK seed account, and closing the WSOL account to recover the remaining SOL.
+
+> All three steps submit real transactions. Set `PRIVATE_KEY` and RPC, use a test wallet first, and reduce amounts as appropriate.
+
+```bash
+cargo run --package wsol_wrapper
+```
+
+Closing WSOL unwraps the account's full remaining balance and removes the account. Do not run that step when another workflow expects the same WSOL account to remain available.

examples/wsol_wrapper/README_CN.md

@@ -0,0 +1,13 @@
+# SOL / WSOL 操作
+
+[English](README.md)
+
+展示包装 SOL、通过 SDK seed 账户部分解包 WSOL，以及关闭 WSOL 账户取回剩余 SOL。
+
+> 三个步骤都会提交真实交易。运行前设置 `PRIVATE_KEY` 和 RPC，先使用测试钱包，并按需降低金额。
+
+```bash
+cargo run --package wsol_wrapper
+```
+
+关闭 WSOL 会解包账户中的全部剩余余额并删除该账户。如果其他流程仍依赖该 WSOL 账户，不要执行关闭步骤。

examples/wsol_wrapper/src/main.rs

@@ -1,6 +1,5 @@
 use sol_trade_sdk::{common::TradeConfig, swqos::SwqosConfig, SolanaTrade};
 use solana_commitment_config::CommitmentConfig;
-use solana_sdk::signature::Keypair;
 use std::sync::Arc;
 
 #[tokio::main]
@@ -80,7 +79,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 /// Create and initialize SolanaTrade client
 async fn create_solana_trade_client() -> Result<SolanaTrade, Box<dyn std::error::Error>> {
     println!("🚀 Initializing SolanaTrade client...");
-    let payer = Keypair::from_base58_string("use_your_payer_keypair_here");
+    let payer = sol_trade_sdk::common::keypair::load_keypair_from_env("PRIVATE_KEY")?;
     let rpc_url = "https://api.mainnet-beta.solana.com".to_string();
     let commitment = CommitmentConfig::confirmed();
     let swqos_configs: Vec<SwqosConfig> = vec![SwqosConfig::Default(rpc_url.clone())];