fix(pool): correct sequence of callback and token transfer in pool swap

[jinoosss]

Descriptions

The Swap function was invoking the safeSwapCallback before transferring the swapped token to the recipient.
This sequence violated the flash swap mechanism invariant, which requires the callback to be executed after the swap output is delivered.

Changes

1. Transfer swapped token before callback (zeroForOne == true):

• Moved safeTransfer for token1 to execute before safeSwapCallback
• Recipient now receives the output token before the callback is invoked

2. Transfer swapped token before callback (zeroForOne == false):

• Moved safeTransfer for token0 to execute before safeSwapCallback
• Recipient now receives the output token before the callback is invoked

Impact

This fix ensures proper flash swap behavior, allowing users to utilize the swapped tokens during the callback execution for arbitrage opportunities or other strategies before repaying the input tokens.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud