feat: Integrate SubscriptionController into wallet initialization

[tuna1207]

Explanation

Adds SubscriptionController as a default initialized unit in @metamask/wallet, with injectable or default SubscriptionService construction and AuthenticationController messenger delegation.

@metamask/wallet is the shared controller-integration layer for extension, mobile, and other clients. Build-specific and runtime values are injected via instanceOptions rather than hardcoded.

Breaking changes

• BREAKING: instanceOptions.subscriptionController is now required with at least env and fetchFunction.
• When passing a full subscriptionService override, env and fetchFunction remain required at the type level but are unused for service construction.

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
Breaking wallet instanceOptions and subscription billing/auth integration require all hosts to supply config and register AuthenticationController; misconfiguration could break subscription API calls but does not directly alter keyring or transaction signing.

Overview
SubscriptionController can now be constructed with either an injected subscriptionService or service config (env, fetchFunction, optional getAccessToken / captureException); the default path builds SubscriptionService and uses AuthenticationController:getBearerToken when no token getter is supplied. The messenger no longer declares unused AuthenticationController:stateChange (AllowedEvents export removed).

@metamask/wallet adds SubscriptionController to default initialization: a required instanceOptions.subscriptionController slot, a new init module that delegates auth actions to the root messenger, dependency on @metamask/subscription-controller, and tests/docs/CODEOWNERS updates. wallet-cli passes { fetchFunction: globalThis.fetch } so the daemon gets production API defaults without extra env wiring.

Changelogs document breaking wallet and subscription-controller API changes; eslint suppressions for removed index.ts exports are cleaned up.

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