feat: Implement FiatStrategy submit flow with order polling and relay execution

[OGPoyraz]

Explanation

Implements FiatStrategy submit flow with order polling and relay execution.

• Implement submitFiatQuotes to poll the on-ramp order via RampsController:getOrder until completion, then re-quote and submit the relay leg with the settled crypto amount
• Add order validation that verifies the completed order's asset and chain match the expected fiat asset before proceeding with relay
• Update relay quote request filtering to support exact-input max amount requests used by the fiat submit re-quote path
• Add orderCode field to TransactionFiatPayment and RampsControllerGetOrderAction to AllowedActions to enable order polling from the fiat strategy
• Fail-closed on terminal order statuses (failed/cancelled), polling timeout with last-status reporting, asset mismatches, and invalid crypto amounts

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

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Note

Medium Risk
Adds a new fiat submission path that polls on-ramp orders and then re-quotes/submits Relay based on the settled amount; mistakes here can cause failed submissions or unexpected amounts. Also changes Relay quote filtering logic, which may affect which quote requests are processed.

Overview
Implements the FiatStrategy submit flow: submitFiatQuotes now polls RampsController:getOrder until completion (with timeout, terminal failure handling, and transient error tolerance), validates the completed order’s asset/chain, converts the settled crypto amount to raw units, re-quotes Relay with an exact-input max-amount request, checks re-quote slippage (5% cap), and submits via submitRelayQuotes.

Updates TransactionPayController so changes to fiatPayment trigger quote refreshes, and changing the fiat payment method attempts to sync RampsController:setSelectedToken (best-effort, errors swallowed). Extends types to include TransactionFiatPayment.orderId and adds RampsController:getOrder/RampsController:setSelectedToken to AllowedActions, plus broad new test coverage for the fiat submit flow and token-selection behavior.

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[OGPoyraz]

Originally we talked Ramps team to add metadata into fiat orders and also filtering mechanism.
Due to limitation of timeframe this may not be option to deliver besides headless ramp, hence we are adding orderCode (meaning order id) into TransactionFiatPayment

[matthewwalsh0]

Minor, orderId or rampsId to be more generic?

[OGPoyraz]

Done - renamed to orderId

[OGPoyraz]

The fiat re-quote request could get dropped by this filter if targetAmountMinimum happened to be '0' - it's not a post-quote, so the second condition wouldn't save it. The isExactInputRequest check distinguishes real exact-input requests (positive source amount + max amount flag) from empty gas fee token requests (zero source amount), ensuring the fiat re-quote passes through.

[matthewwalsh0]

Minor, orderId or rampsId to be more generic?

[cursor]

Slippage check skips when re-quoted amount is zero

Medium Severity

validateRelaySlippage early-returns when either original or reQuoted is not positive. Skipping when the original is zero is correct (can't compute percentage slippage), but also skipping when the re-quoted amount is zero silently accepts a 100% loss scenario. The test only covers the "original is zero" case, confirming the developer's intent was narrower than what the || condition implements.

 

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[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

There are 2 total unresolved issues (including 1 from previous review).

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