feat(perps): double fee for hip-3 assets

[abretonc7s]

Description

Implement 2x fee multiplier for HIP-3 (HyperLiquid Improvement Proposal 3) assets as per HyperLiquid protocol specification.

What changed:

• HIP-3 assets (identified by dex:SYMBOL format like xyz:TSLA) now have 2x base exchange fees
• Regular assets (e.g., BTC, ETH) are unaffected

Why:
HyperLiquid protocol charges double base fees for builder-deployed perpetuals (HIP-3 assets):

• Regular taker: 0.045% -> HIP-3 taker: 0.090%
• Regular maker: 0.015% -> HIP-3 maker: 0.030%

How:
Applied 2x multiplier to all three fee rate sources:

1. Base rates (when no user-specific rates available)
2. Cached user rates (from fee cache)
3. API-fetched user rates (from HyperLiquid API)

Changelog

CHANGELOG entry: Fixed HIP-3 perpetuals to display correct 2x exchange fees

Related issues

Fixes: https://consensyssoftware.atlassian.net/browse/TAT-1950

Manual testing steps

Feature: HIP-3 Fee Display

  Scenario: user views fees for HIP-3 asset
    Given user is on Perps trading screen

    When user selects a HIP-3 asset (e.g., "xyz:XYZ100")
    And user enters a trade amount
    Then fee modal should show provider fee ~0.086% (2x base rate)
    And total fee should be ~0.186% (provider + 0.1% MetaMask)

  Scenario: user views fees for regular asset
    Given user is on Perps trading screen

    When user selects a regular asset (e.g., "BTC")
    And user enters a trade amount
    Then fee modal should show provider fee ~0.043% (base rate)
    And total fee should be ~0.143% (provider + 0.1% MetaMask)

Screenshots/Recordings

Before

HIP-3 assets showed incorrect 0.043% provider fee (missing 2x multiplier)

After

HIP-3 assets correctly show 0.086% provider fee (2x multiplier applied)

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Mobile Coding Standards
• I've completed the PR template to the best of my ability
• I've included tests if applicable (225 tests passing, added HIP-3 validation test)
• I've documented my code using JSDoc format if applicable
• I've applied the right labels on the PR

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed)
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots

---

Technical Details

Files Modified:

• app/components/UI/Perps/controllers/types/index.ts - Added coin parameter to FeeCalculationParams
• app/components/UI/Perps/controllers/providers/HyperLiquidProvider.ts - Applied HIP-3 2x multiplier to all rate sources
• app/components/UI/Perps/controllers/PerpsController.ts - Updated method signature
• app/components/UI/Perps/hooks/usePerpsOrderFees.ts - Pass coin parameter
• app/components/UI/Perps/hooks/usePerpsCloseAllCalculations.ts - Pass coin parameter
• Test files - Updated all tests to pass coin parameter

Test Coverage:

• All existing tests passing (225/225)
• Added hip3-fee-validation.test.ts with 8 validation tests
• Verified HIP-3 detection logic
• Verified 2x multiplier application

Key Implementation:

// Detect HIP-3 assets by colon separator
const { dex } = parseAssetName(coin); // "xyz:TSLA" -> dex="xyz"
const isHip3Asset = dex !== null;

// Apply 2x multiplier to all rate sources
if (isHip3Asset) {
  feeRate *= 2;
}

---

Note

Implements a 2× fee multiplier for HIP-3 (dex:SYMBOL) assets and updates fee calculation to require coin, applying the multiplier across base, cached, and API-fetched rates with comprehensive test updates.

• Fees/HIP-3:
  • Add HIP3_FEE_CONFIG with FEE_MULTIPLIER: 2 in constants/hyperLiquidConfig.ts.
  • Apply 2× multiplier for HIP-3 assets (detected via parseAssetName(coin)) in HyperLiquidProvider.calculateFees() for:
    • Base rates
    • Cached user rates
    • API-fetched user rates
• API/Types:
  • Make coin required in FeeCalculationParams (controllers/types).
  • Update PerpsController.calculateFees signature to accept FeeCalculationParams and forward to provider.
• Hooks/Usage:
  • Pass coin to fee calc in usePerpsOrderFees and usePerpsCloseAllCalculations.
• Tests:
  • Update all fee tests to include coin.
  • Add tests verifying 2× HIP-3 fees for taker/maker in HyperLiquidProvider.test.ts.
  • Minor test cleanups (remove unused placeholders, add isFeeCacheValid edge case).

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[github-actions]

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[michalconsensys]

👍 looks good, I've left there 2 questions