feat(forge): migrate FastAPI DNF history

[fronzec]

Problem

The public fronzec/fastapi-projects repository contains a DNF history API that belongs in Forge's concept-first catalog. Its source image is end-of-life and the required history input is not committed.

Proposed change

• Migrate the synchronized hello-world snapshot without Git history.
• Place it under rest-api/system-history/python-fastapi/.
• Add a safe fixture, pinned dependencies, current Python container, HTTP request, and Forge experiment record.
• Preserve the bounded asynchronous parsing behavior.

Acceptance criteria

• Source main was synchronized with git pull --ff-only origin main.
• The snapshot records source commit 7a35799.
• Dependency compatibility, import, and live HTTP behavior pass on Python 3.11.
• The unavailable Podman runtime is documented without claiming a container build.

Pre-flight

• Existing issues were searched and no duplicate was found.
• This migration is explicitly approved by the maintainer.