fix: evaluated positive or negative balanceDiff to put transactions in from or to

[gabrieledm]

Explanation

Fixes incorrect transaction direction and type detection when the fee payer receives an amount of SOL that is less than or equal to the transaction fee.
Previously, native transfer direction was determined using the raw pre and post transaction balances.
For a USDC-to-SOL swap, the fee payer’s balance can still decrease when the received SOL is smaller than the fee.
This caused the incoming SOL to be classified as outgoing and could prevent the transaction from being identified as a swap.

The mapper now determines direction from the fee-adjusted balance difference:

• Positive difference -> outgoing SOL
• Negative difference -> incoming SOL
• Zero difference -> fee-only balance change, not a transfer

References

Fixes MetaMask/metamask-extension#43164

Changes

• Use the fee-adjusted SOL balance difference to determine native transfer direction.
• Ignore SOL balance decreases caused exclusively by transaction fees.
• Update the existing swap expectation to reflect the correct native SOL direction.
• Add tests covering incoming SOL amounts that are:
  • Less than the transaction fee
  • Equal to the transaction fee
  • Greater than the transaction fee
• Add equivalent coverage for SPL-token-to-native-SOL swaps.
• Use fresh mapper dependencies in the new parameterized tests to prevent mock state from leaking between cases.

Testing

• Added native SOL transfer boundary tests around the transaction fee.
• Added a fee-only transaction test.
• Added SPL-token-to-SOL swap classification tests for all fee boundary cases.

Before

WPN-1223.Before.mov

After

WPN-1223.After.mp4

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them