feat: add confirmation dialog before sendTransfer and before signing a PSBT from the keyring handler

[Battambang]

Explanation

This PR contributes to supporting the Bitcoin dApp connectivity.
It's adding the a confirmation dialog to the user before a dApp calling for a sendTransfer() and before signing a PSBT from the keyring handler entrypoint.

It is part from the initial PR #564 feat: enable account address resolution to support dApps connectivity to split the work into 3 smaller PRs:
#589 refactor: move validation structs and add account field
#590 feat: add resolveAccountAddress method to KeyringHandler for dApp connectivity routing
#591 feat: add confirmation dialog before sendTransfer and before signing a PSBT from the keyring handler

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

Medium Risk
Adds new user-confirmation gates to signPsbt and sendTransfer flows and introduces resolveAccountAddress routing, changing how keyring requests are validated and executed. Moderate risk due to impacting transaction signing/sending UX and request routing/validation paths.

Overview
Adds explicit confirmation UX before executing keyring-initiated signPsbt and sendTransfer, including a new SignPsbtConfirmationView that displays parsed outputs, fees, and sign options (with best-effort fiat exchange rate lookup).

Extends keyring support with KeyringRpcMethod.ResolveAccountAddress (KeyringHandler.resolveAccountAddress) so MetaMask can route BTC dapp signing requests to the right account, and tightens request validation by requiring an account: { address } param across BTC wallet request structs.

Updates sendTransfer to only allow a single recipient, honor frozen UTXOs, and build the PSBT with fee rate/unspendables before confirmation; tests and locales are updated accordingly.

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[Battambang]

@metamaskbot publish-preview

[github-actions]

Preview builds have been published. See these instructions for more information about preview builds.

Expand for full list of packages and versions.

{
  "@metamask-previews/bitcoin-wallet-snap": "1.10.0-preview-89127a1"
}