chore: #12184 MVP split engine file

[Cal-L]

Description

This PR establishes a pattern for splitting out controllers from the main Engine.ts file, which provides the following benefits

• Reduce friction regarding code ownership especially during reviews (this is the main purpose of this effort)
• Easier to manage, test, and handling controller initialization failures

The POC here applies to the AccountsController initialization logic, which has been mostly abstracted out into AccountsController directory. This pattern should be applicable to other controllers in the Engine file as well.

This pattern also enables us to redirect users to vault recovery in the event of controller initialization failures and should reduce the chances of users being "bricked". These changes may be introduced in future interations

Related issues

Fixes: #12184

Manual testing steps

The changes should not affect app behavior

• Run the app as usual
• Ensure that everything behaves as usual (Auth, dapp connections, navigation, etc)

Screenshots/Recordings

Before

After

App still runs normally

https://github.com/user-attachments/assets/dc7fc017-1a26-4681-b84a-e04c63952281

Pre-merge author checklist

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

Pre-merge reviewer checklist

• [x] I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• [x] 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.

[github-actions[bot]]

CLA Signature Action: All authors have signed the CLA. You may need to manually re-run the blocking PR check if it doesn't pass in a few minutes.

[github-actions[bot]]

Bitrise

✅✅✅ pr_smoke_e2e_pipeline passed on Bitrise! ✅✅✅

Commit hash: 8443cc7c39d35b804f362892a6130188495e1ddc Build link: https://app.bitrise.io/app/be69d4368ee7e86d/pipelines/897a1c5f-e79a-4635-af2f-d45d7ade7e75

[!NOTE]

• You can kick off another pr_smoke_e2e_pipeline on Bitrise by removing and re-applying the Run Smoke E2E label on the pull request

[sonarcloud[bot]]

Quality Gate failed

Failed conditions
53.7% Coverage on New Code (required ≥ 60%)

See analysis details on SonarQube Cloud

[Cal-L]

Skipping sonar failure (Engine.ts) since this PR just removes code from the file

[github-actions[bot]]

Bitrise

✅✅✅ pr_smoke_e2e_pipeline passed on Bitrise! ✅✅✅

Commit hash: f69b6d3682966c456a6dd4e36f412a6511be5385 Build link: https://app.bitrise.io/app/be69d4368ee7e86d/pipelines/e8068757-a06a-41a0-900c-d02ca1f04e4b

[!NOTE]

• You can kick off another pr_smoke_e2e_pipeline on Bitrise by removing and re-applying the Run Smoke E2E label on the pull request