Improve error message extraction in poll_transaction_confirmation to:
- Collect multiple error messages instead of stopping at the first one
- Add support for "Program log: Error: " format in addition to "Error Message: "
- Concatenate multiple errors with semicolon separator for comprehensive error reporting
- Add TradeError struct with code, message, and instruction fields
- Enhance poll_transaction_confirmation to extract detailed error info from logs
- Change buy/sell return type from Option<anyhow::Error> to Option<TradeError>
- Add solana-transaction-status-client-types dependency
- Remove unused parallel.rs module
ysq