test: extend statistics test coverage

[Japrolol]

Issue(s)

1354

Overview

Extends E2E coverage for statistics across admin analytics and course-level statistics.

Adds statistics-specific handles, flows, and specs covering:

• Admin analytics dashboard chart rendering.
• Admin analytics summary report download.
• Course statistics role access, with admin visibility and student restriction.
• Course statistics overview, student progress, search, group filtering, quiz results, quiz
  filtering, and learning-time table visibility.
• AI mentor statistics using prepared mentor progress through a test-config fixture endpoint
  instead of real AI chat/judge calls.

Adds stable data-testid hooks across course statistics tables, filters, overview cards, preview
actions, lesson preview dialog, course statistics tab, AI mentor messages, and admin analytics
charts. Also adds a typed generated API client path for preparing deterministic AI mentor
statistics data in tests.

Business Value

Improves confidence that admins can access and use statistics dashboards reliably, including
course progress, quiz results, AI mentor results, filters, and report downloads.

The deterministic AI mentor statistics setup avoids spending time and money on real AI calls in
E2E while still validating the statistics UI and backend integration path.

[github-actions]

🚀 Preview ready

Mails do not leave the preview environment. Database has been seeded with test data. You can access the preview at the following URLs:

List of available services:

Service	URL
Web	https://pr-1459.beta.mentingo.com
Mailhog	https://mailhog-pr-1459.beta.mentingo.com

List of available accounts:

Role	Email	Password
Student	student@example.com	password
Student	student0@example.com	password
Student	student2@example.com	password
Content Creator	contentcreator@example.com	password
Content Creator	contentcreator2@example.com	password
Admin	admin@example.com	password