Launch a cmi5 Assignable Unit with correct fetch URL handling and session state tracking

Steps

1. The LMS constructs the AU launch URL by appending required query string parameters: endpoint (LRS xAPI endpoint), fetch (one-time fetch URL for the authorization token), registration, activityId, and optionally actor and returnURL
2. The AU calls the fetch URL via HTTP POST to exchange it for a single-use authorization token; the fetch URL is one-time-use only and must not be called more than once
3. The AU uses the retrieved authorization token as the Bearer token for all xAPI statements sent to the LRS endpoint during the session
4. The AU sends the required cmi5-defined xAPI statements in order: initialized (on load), then passed/failed/completed as appropriate, then terminated (on close); these must use the cmi5 category activity ID
5. The LMS tracks session state via the xAPI State API (using the cmi5LearnerPreferences and LMS.LaunchData state resources) rather than SCORM's session variables; implement state reads before the AU begins its interaction