feat(transaction-pay-controller): slippage tokens feature flag

[matthewwalsh0]

Explanation

• What is the current state of things and why does it need to change?
  Previously, the TransactionPayController used a single, global slippage value configured via the slippage feature flag or a static default. This lacked the granularity to set different slippage tolerances for specific tokens or chains, which may be necessary due to varying liquidity or volatility.

• What is the solution your changes offer and how does it work?
  This PR introduces a new slippageTokens feature flag, allowing slippage values to be defined per chain ID and token address. A new getSlippage utility function has been added to feature-flags that retrieves the most specific slippage value:

  1. Token-specific slippage (from slippageTokens)
  2. General slippage (from the slippage feature flag)
  3. A static default (0.005)

  The relay-quotes strategy has been updated to use this new getSlippage utility.

• Are there any changes whose purpose might not obvious to those unfamiliar with the domain?
  The lookup for both chain ID and token address within the slippageTokens feature flag and the getSlippage utility is case-insensitive to ensure flexibility in configuration.

References

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

---

 

---

Note

Adds configurable, token-specific slippage to Transaction Pay.

• New slippageTokens feature flag and getSlippage(messenger, chainId, tokenAddress) utility with case-insensitive lookups and fallback to general slippage then DEFAULT_SLIPPAGE
• Relay strategy (relay-quotes.ts) now derives slippageTolerance from getSlippage instead of global flag
• Expanded tests for feature flags and Relay quotes to cover token-specific slippage behavior
• Updated CHANGELOG.md to document the new flag

^{Written by Cursor Bugbot for commit b510cfa. This will update automatically on new commits. Configure here.}

[cursor]

Cursor Agent can help with this pull request. Just @cursor in comments and I'll start working on changes in this branch.
_{Learn more about Cursor Agents}