Google Classroom Assignment Lifecycle for App Inventor

Teachers cannot assign, collect, or grade App Inventor projects through their LMS. They share project links manually, collect screenshots, and enter grades by hand. This project builds a Google Classroom integration so teachers can create assignments linked to template projects, students can submit completed projects to Classroom, and teachers can return grades without leaving their normal workflow. The backend introduces an LmsService interface so that adding Canvas or Moodle support later requires only a new provider class. Deliverables are tiered: minimum (OAuth2 plus course listing plus assignment creation), target (full create-distribute-submit lifecycle with error handling), and stretch (GWT UI plus grade passback plus integration tests).