Description

Adds two SecureKeychain-backed stores for the Card feature. These stores will be used by the CardController (merged in #27020) to manage auth tokens and onboarding session data.

Why: Card auth tokens already live in SecureKeychain via cardTokenVault.ts, but the API is tightly coupled to a single provider. Onboarding session data (onboardingId, contactVerificationId, consentSetId).

What changed:

• CardTokenStore.ts (~90 lines): SecureKeychain wrapper for auth tokens keyed by provider ID. For the legacy provider, reads from the same keychain scope as cardTokenVault.ts (com.metamask.CARD_BAANX_TOKENS) — zero migration, both old and new code can coexist. New providers get their own scoped keychain entry. Methods: get(providerId), set(providerId, tokenSet), remove(providerId). All errors caught and logged with structured Sentry context.

• CardOnboardingStore.ts (~100 lines): SecureKeychain wrapper for onboarding session data keyed by provider ID. Stores onboardingId, contactVerificationId, consentSetId, and selectedCountry. The set() method merges partial data with existing data (read-modify-write). Scope: com.metamask.CARD_ONBOARDING_{providerId}. Intentionally not populated in this PR — it will only be written to when the new controller code path is active (Phase 1d).

• CardTokenStore.test.ts (151 lines): 8 tests covering retrieval (null, valid, legacy scope, provider-specific scope, invalid data, keychain error), storage (success, failure, error), and removal.

• CardOnboardingStore.test.ts (162 lines): 8 tests covering retrieval (null, merged with defaults, correct scope, error), storage (merge with existing, create from empty, error), and removal.

Important design decision: Neither store is populated during a Redux migration. Onboarding data stays in Redux until the code path switch (Phase 1d), avoiding stale data issues where old code clears Redux via dispatch(resetOnboardingState()) but has no knowledge of the keychain store. Auth tokens already exist in keychain — CardTokenStore reads the same data, no write needed.

Changelog

CHANGELOG entry: null

Related issues

Fixes:

Manual testing steps

Feature: Keychain stores are inert

  Scenario: No user-facing changes
    Given the user is on any screen in the app
    When the app loads
    Then nothing visually changes
    And the Card feature continues to work as before
    And no data is written to CardTokenStore or CardOnboardingStore

  Scenario: Existing card auth tokens are unaffected
    Given the user is authenticated with the Card feature
    When the app updates to this version
    Then the user remains authenticated
    And cardTokenVault.ts continues to read/write tokens as before

Screenshots/Recordings

No UI changes — this is an infrastructure-only PR.

Before

Auth tokens managed by cardTokenVault.ts. Onboarding data in plaintext Redux.

After

CardTokenStore and CardOnboardingStore exist alongside existing code. Neither is actively used yet — they are wired in during Phase 1d (code path switch). Existing behavior is unchanged.

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Mobile Coding Standards.
• I've completed the PR template to the best of my ability
• I've included tests if applicable
• I've documented my code using JSDoc format if applicable
• I've applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.