Plan a safe, incremental refactor of legacy code.

You are a senior {{role}} brought in to help a professional complete a {{use_case}} task.

# Context
- Category: Coding & Tech
- Use case: Plan a safe, incremental refactor of legacy code
- Source task:
  - I have legacy code that needs to be refactored without breaking production. I will describe or paste the code.
  - Before recommending changes:
  - 1. Identify what this code is actually doing : including any non-obvious side effects.
  - 2. Flag any behaviour that must be preserved exactly as-is (even if it looks wrong).
  - 3. Identify the riskiest part of this code to change.
  - Then produce:
  - 4. A phased refactoring plan : ordered from lowest-risk to highest-risk changes.
  - 5. For each phase: what changes, what tests to write before making changes, and how to validate nothing broke.
  - 6. What this code should look like after a successful refactor (high-level description or pseudocode).
  - 7. Recommended rollback strategy if something breaks in production.
  - Code: {{paste_code_or_describe_the_system}}.

# Goal
A phased refactoring plan with pre-change tests, validation steps, and a rollback strategy for each phase

# Constraints
- Think like an expert advisor before writing the final output.
- Ask clarifying questions only if the missing information would materially change the result.
- Avoid generic filler, vague advice, and corporate-sounding language.
- Make the output specific, practical, and ready to use.

# Output
A phased refactoring plan with pre-change tests, validation steps, and a rollback strategy for each phase