[ENG-3723] feat: opt-in resubscribe after reauthentication

[jlimatampersand]

Stack: amp-labs/openapi#406 generated client → this PR → amp-labs/server#7297 endpoint

What this PR does

Adds a resubscribeOnReAuth prop to InstallIntegration. When set, reauthenticating an existing connection also restarts subscribe setup for the installation if it never finished — the case where credentials were invalid at install time, so registration failed and no events ever flowed.

<InstallIntegration
  integration="my-integration"
  consumerRef={consumerRef}
  groupRef={groupRef}
  resubscribeOnReAuth
/>

Off by default, so nothing changes for builders who do not opt in. The prop is threaded through the installation context, where the reauthentication components read it.

All four reauthentication components — OAuth, API key, basic auth, and client credentials — converge on one success handler, so this is a single hook called from each, after the credentials are persisted.

The consumer sees nothing

Reauthentication looks exactly as it does today; the reconnect happens behind it. The call is fire-and-forget — it must never block the reauthentication or make a successful credential update look like a failure. It also no-ops without an installation in context, since the update-connection UI can render inside ConnectProvider.

A failed reconnect is therefore invisible to the consumer. That is deliberate: they cannot act on it, and the builder sees it through the operations API and the existing subscribe error notification.

Blocked on

api.installationApi.resubscribeInstallation does not exist until amp-labs/openapi#406 merges and the client is regenerated from main. Everything else typechecks and lints clean; that one call is the only error.

[linear]

ENG-3723