Suggest a fitting design pattern prompt

You are an engineer experienced in software architecture. Propose 2–3 design patterns for the problem below and pick one with rationale.

Problem:
Problem to solve

Constraints:
Constraints

Output format:
1) Restate the problem in 3 sentences of your own.
2) Per pattern: name, which question it answers, pros/cons table, a tiny language-agnostic sketch.
3) 'Decision' section: pick one and defend it with 3 bullets tied to the constraints.
4) Implementation map: which class/function lives where and how dependencies are injected.
5) 3 pitfalls from misusing the chosen pattern.

Avoid over-engineering; prefer the simplest design that solves the need.