fix: default usd_amount_source

[infiniteflower]

Explanation

This PR fixes issues with non-EVM chains metrics fields: usd_amount_source, usd_quoted_gas, and usd_quoted_return being empty.

BTC > Ethereum ETH

{
  "event": "Unified SwapBridge Submitted",
  "properties": {
    "action_type": "swapbridge-v1",
    "chain_id_destination": "eip155:1",
    "chain_id_source": "bip122:000000000019d6689c085ae165831e93",
    "token_symbol_destination": "ETH",
    "token_symbol_source": "BTC",
    "usd_amount_source": 8.552348546334175,
    "usd_quoted_gas": 0.1528316510665362,
    "usd_quoted_return": 8.077899232411106
  }
}

Solana USDC > Ethereum USDC

{
  "event": "Unified SwapBridge Submitted",
  "properties": {
    "action_type": "swapbridge-v1",
    "chain_id_destination": "eip155:1",
    "chain_id_source": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "token_symbol_destination": "USDC",
    "token_symbol_source": "USDC",
    "usd_amount_source": 7.610396854485804,
    "usd_quoted_gas": 0.0004258844456526694,
    "usd_quoted_return": 7.509516072087331
  }
}
{
  "event": "Unified SwapBridge Completed",
  "properties": {
    "action_type": "swapbridge-v1",
    "actual_time_minutes": 0.7352166666666666,
    "chain_id_destination": "eip155:1",
    "chain_id_source": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "token_symbol_destination": "USDC",
    "token_symbol_source": "USDC",
    "usd_actual_gas": 0,
    "usd_actual_return": 7.509941956532984,
    "usd_amount_source": 7.610396854485804,
    "usd_quoted_gas": 0.0004258844456526694,
    "usd_quoted_return": 7.509941956532984
  }
}

Solana SOL > Solana USDC

{
  "event": "Unified SwapBridge Submitted",
  "properties": {
    "action_type": "swapbridge-v1",
    "chain_id_destination": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "chain_id_source": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "token_symbol_destination": "USDC",
    "token_symbol_source": "SOL",
    "usd_amount_source": 2.279447465339925,
    "usd_quoted_gas": 0.000425849999999986,
    "usd_quoted_return": 2.267409556725925
  }
}
{
  "event": "Unified SwapBridge Completed",
  "properties": {
    "action_type": "swapbridge-v1",
    "actual_time_minutes": 0,
    "chain_id_destination": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "chain_id_source": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "token_address_destination": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp/token:EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "token_address_source": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp/slip44:501",
    "token_symbol_destination": "USDC",
    "token_symbol_source": "SOL",
    "usd_actual_gas": 0,
    "usd_actual_return": 0,
    "usd_amount_source": 2.279447465339925,
    "usd_quoted_gas": 0.000425849999999986,
    "usd_quoted_return": 2.267835406725925
  }
}

References

Fixes: https://consensyssoftware.atlassian.net/browse/SWAPS-3592
Fixes: https://consensyssoftware.atlassian.net/browse/SWAPS-4121

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

Medium Risk
Changes exchange-rate derivation logic for non-EVM chains and alters emitted metrics defaults; risk is mainly incorrect USD calculations if currencyRates is missing or inconsistent.

Overview
Fixes metrics gaps for non-EVM swaps/bridges by deriving usdExchangeRate from multichain asset rates using an inferred user-currency→USD conversion factor, enabling usd_amount_source, usd_quoted_gas, and usd_quoted_return to be populated.

Also changes EVM transaction metrics defaults so usd_amount_source is 0 instead of 100, and updates/expands unit tests and snapshots accordingly; both packages’ changelogs are updated.

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