feat(keyring-snap-bridge): add SnapKeyringV1Adapter

[ccharly]

A more specialized adapter for the SnapKeyring v2 instances. For recall, each v2 instances are being wrapped in a v1 equivalent adapter since the KeyringController requires it.

We now have a more specific one mostly to address a different implementation of removeAccount (it always had been async even in the legacy Snap keyring) AND the KeyringController already await for this call.

---

Note

Low Risk
Small, focused adapter with tests; account removal behavior is intentional compatibility with KeyringController, not new crypto or auth logic.

Overview
Introduces SnapKeyringV1Adapter, a thin wrapper around v2 SnapKeyring so it can be used where KeyringController still expects the legacy v1 keyring surface.

Most v1 behavior (including EVM signing) comes from EthKeyringV1Adapter in @metamask/keyring-sdk. This PR adds Snap-specific removeAccount(address): resolve the account by address, then deleteAccount by id—matching the legacy Snap keyring’s async removal flow that the controller already awaits.

The adapter is exported from @metamask/keyring-snap-bridge/v2, documented in the package changelog, and covered by unit tests for generic v1 adapter behavior and account removal errors.

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[ccharly]

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Preview builds have been published. See these instructions (from the core monorepo) for more information about preview builds.

Expand for full list of packages and versions.

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