Retrieve a Brightspace learner's scheduled and overdue content items across their courses via the Valence Content API myItems endpoints

Steps

1. Get an access token for the calling user context (own-data endpoints don't require elevated admin scopes beyond normal authentication).
2. GET /d2l/api/le/{version}/content/myItems/ with an orgUnitIdsCSV query parameter (up to 100 org unit IDs from the user's active enrollments) to list all of the user's scheduled items, sorted by earliest start/end/due date.
3. Narrow to only items still due with GET /d2l/api/le/{version}/content/myItems/due/, or get counts instead of full records with /content/myItems/itemCounts/ and /content/myItems/due/itemCounts/.
4. Filter any of these calls further with the optional completion, startDateTime, and endDateTime query parameters (COMPLETION_T values: Any=1, CompletedOnly=2, NotCompletedOnly=3).
5. For a single org unit's items for the current user, call GET /d2l/api/le/{version}/{orgUnitId}/content/myItems/ instead; for an administrator or advisor view of another user's items, call GET /d2l/api/le/{version}/content/items/{userId} (requires permission to see user progress, manage content, and see the classlist in every listed org unit).