[10] feat(checkout): fiat-first cash funding with live on-ramp quotes

[tomiiide]

Which Linear task is linked to this PR?

EMB-464 — Quote-aware Transak funding: live quote + dynamic fiat currencies

Why was it implemented this way?

This branch builds on checkout/09-wallet-any-route and replaces the faked cash quote (CheckoutFlowCtaButton computing fiatAmount = cryptoAmount × priceUSD, hardcoded USD/EUR/GBP) with the Core API's quote-aware Transak endpoints.

• Fiat-first input. The cash flow now takes a fiat amount (cashFiatAmount) with presets and currency/payment-method selection driven by /v1/checkout/onramp/fiat-currencies. A debounced /v1/checkout/onramp/quote derives the crypto route amount, fees, and guaranteed minimum, gating the CTA until the quote and route agree.
• Dynamic currencies. fiatCurrency is no longer a USD/EUR/GBP union; currencies, symbols, and names come from the API and Intl (fiatFormat/currencyToFlag), with the static list kept only as a fallback.
• Session metadata for reconciliation. fundingSessionId is carried through OnRampSession state, the Transak/Mesh hosts, the checkout CheckoutResult, and the persisted pending record (bumped to v5) so resume/reconciliation can match the provider order.
• Transak hand-off. A bottom sheet confirms the temporary deposit-address hand-off before launching Transak.

Visual showcase (Screenshots or Videos)

Not included; recommend a playground pass on the cash flow: pick a currency/payment method, type a fiat amount, confirm the receive card shows a live quote (fees + guaranteed minimum) and the CTA enables once the route matches.

Checklist before requesting a review

• I have performed a self-review and testing of my code.
• This pull request is focused and addresses a single problem.
• If this PR modifies the Widget API or adds new features that require documentation, I have updated the documentation in the public-docs repository.

[changeset-bot]

🦋 Changeset detected

Latest commit: 54f351e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 14 packages

Name	Type
@lifi/widget-provider	Minor
@lifi/widget-provider-transak	Major
@lifi/widget-provider-mesh	Major
@lifi/widget-checkout	Minor
@lifi/widget	Minor
@lifi/wallet-management	Patch
@lifi/widget-provider-bitcoin	Patch
@lifi/widget-provider-ethereum	Patch
@lifi/widget-provider-solana	Patch
@lifi/widget-provider-sui	Patch
@lifi/widget-provider-tron	Patch
vite-iframe	Patch
nft-checkout	Patch
tanstack-router-example	Patch

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