Your personal operating system for career transition.

Implement a prompt version registry with promotion logic

Prompt changes that degrade quality need to be detectable and rollback-able. This exercise builds the minimal data structure for version-controlled prompts.

What you are building

Implement a PromptRegistry class that manages versioned prompt templates per feature:

Methods to implement:

• create(feature: str, template: str, variables: list[str]) -> int — Create a new draft version. Returns the version number.
• promote(feature: str, version: int) -> None — Promote a draft version to production. Retires the previous production version.
• get_active(feature: str) -> dict | None — Return the current production version dict (with feature, version, template, variables, status).
• rollback(feature: str) -> bool — Restore the most recently retired version to production. Returns True if successful, False if no retired version exists.
• list_versions(feature: str) -> list[dict] — Return all versions for a feature, sorted by version number ascending.

Requirements

• Versions auto-increment per feature starting at 1
• Only one version per feature can be in "production" status at a time
• Promoting a version sets its status to "production" and the previous production version to "retired"
• Status values: "draft", "production", "retired"
• Store everything in-memory (a dict is fine)