feat: add resolveAccountAddress method to KeyringHandler for dApp connectivity routing

[Battambang]

Explanation

This PR contributes to supporting the Bitcoin dApp connectivity.
It's adding the resolve account address Keyring method.

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

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Note

Medium Risk
Adds a new keyring RPC method that influences how incoming signing requests are routed to accounts, and tightens request validation to require an account.address field; mismatches could cause requests to fail or route incorrectly.

Overview
Adds KeyringRpcMethod.ResolveAccountAddress support in KeyringHandler, implementing resolveAccountAddress(scope, request) to validate the scope/request shape, find a matching account by params.account.address, and return a CAIP-style ${scope}:${address} identifier (or null on any validation/match failure).

Updates Bitcoin keyring request validation by centralizing request structs in handlers/validation.ts (now including account: { address } and a BtcWalletRequestStruct union keyed by BtcMethod), refactors KeyringRequestHandler to use these shared validators, and adjusts unit/integration tests accordingly. Also updates the Snap CHANGELOG and manifest shasum.

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[Battambang]

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[github-actions]

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

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{
  "@metamask-previews/bitcoin-wallet-snap": "1.10.0-preview-4a5f56f"
}