feat: Cohort Learning — Course & Lesson Discussions, Completion Hero, E2E Refactor - hackaton

[kpazgan]

Summary

This PR introduces the Cohort Learning feature suite, enabling collaborative learning through course and lesson discussions, a course completion hero, and includes a comprehensive E2E test infrastructure refactor.

What's New

Cohort Learning Core

• Course Discussions — Discussion threads at course level with moderation controls
• Lesson Discussions — Discussion threads attached to individual lessons
• Discussion Schema & API — Full backend support with endpoints for threads and comments
• Course Completion Hero — Celebration UI for students who finish a course
• Global Toggle — Admin setting to enable/disable cohort learning per tenant

Frontend

• New CourseDiscussions tab and workspace components
• LessonDiscussion workspace integration
• Discussion mutation/query hooks (useDiscussions, useToggleCohortLearning)
• Updated course view sidebar and lesson layouts
• i18n translations for all new features

Backend

• course-discussions module with controller, service, repository
• Database migrations for discussions, cohort learning settings, and tenant RLS
• Updated generated-api.ts with new endpoints

E2E Tests (Major Refactor)

• Replaced monolithic test files with factory + flow + spec architecture
• Added factories for courses, users, groups, articles, news, Q&A, tenants, etc.
• Reusable flow files for common actions (auth, courses, curriculum, users, etc.)
• New isolated specs covering: AI mentor, announcements, articles, auth, categories, course enrollment, curriculum, environment, groups, i18n, learning, navigation, news, Q&A, tenants, users
• Added Firefox nightly E2E workflow
• Updated Playwright config and CI workflows

Infrastructure

• Updated GitHub Actions workflows (removed old staging deploys, updated demo/pr previews)
• Added CONTEXT.md for domain terminology
• Package bumps in apps/api/package.json

Migration Notes

• Run new database migrations (0107–0111)
• No breaking changes to existing features

Video

• admin part:

admin.mp4

• student part:

student.mp4

Testing

• Unit tests pass (web & api)
• E2E tests pass
• Verified discussions CRUD
• Verified completion hero render