Implement code question-answer workflow

What does this merge request do and why?

This MR implements the code question-answer workflow as part of the agent factory approach.

How to set up and validate locally

1. Check out to this merge request's branch.
2. Install dependencies.

   mise install # we require sqlite3 additionally
   poetry run install

3. Clone the desired repo to ask questions about.
4. Update eli5/agentfactory/.example/qa_code/task.yml with the question and repository path.
5. Run the experiment:

    poetry run eli5 agent-factory run eli5/agentfactory/.example/qa_code

Merge request checklist

• Tests added for new functionality. If not, please raise an issue to follow up.
• Documentation added/updated, if needed.