Plan mode brief before touching code

Before writing or editing a single line, stay in plan mode.

Context for the work:
- Repo or folder: [PATH]
- Result I want: [GOAL IN ONE SENTENCE]
- What CANNOT be touched: [UNTOUCHABLE FILES, PATHS OR BEHAVIORS]
- How we check it worked: [COMMAND, TEST OR EVIDENCE]

Your plan has to answer, in this order:
1. Which files you will read before deciding, and why those and not others.
2. What you will change, file by file, one line each.
3. What you will deliberately leave untouched.
4. What this change could break and how you will detect it.
5. The exact command I will use to verify the result.

Rules:
- If the goal is ambiguous, do not choose for me. Tell me what the ambiguity is and which decision changes the work.
- If the plan touches more than [N] files, stop and propose how to split it into steps that can be reviewed separately.
- Do not include steps you cannot verify.
- Do not propose refactors I did not ask for. If you see something worth fixing, note it separately at the end of the plan.

Do not leave plan mode until I approve. Planning badly costs minutes; implementing badly costs twice that to revert.