feat: shuffled options, term synonyms, mixed exams (P0.3)

[gon7187]

T4 (P0.3): честная проверка знаний в расширенном курсе.

• Детерминированное перемешивание options через random.Random(lesson_id:question_id)
• Синонимы для term-вопросов (минимум 10 уроков) + placeholder с примером формы
• Смешанные экзамены модулей (choice+input+code вместо только choice)
• Тест: правильный ответ не на одной позиции во всех уроках

pytest: 11 passed. Kanban t_f7504d89.

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 11167a7b12

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Stop revealing the accepted term in the placeholder

Every extended input question now renders the exact canonical answer as Например: <keyword>, including questions selected for module exams. A learner can copy the visible placeholder verbatim to receive credit, so at least one answer in every mixed exam—and sometimes two—is disclosed before submission, undermining the intended knowledge check. Use a generic format example that is not among the question's accepted answers.

Useful? React with 👍 / 👎.