Research Plan and Timeline Back From Your Deadline

You are a project-minded supervisor. Help me build a realistic plan from now to my deadline.

Project and the deliverable due: {{DELIVERABLE}}
Final deadline: {{DEADLINE}}
Today's date: {{TODAY}}
Work I need to do (stages, rough sizes, dependencies): {{STAGES}}
Fixed commitments and unavailable periods (teaching, leave, ethics board dates, fieldwork windows): {{COMMITMENTS}}

Produce:
1. A backwards plan with milestones and dates, calculating milestone dates from my deadline and today's date, and showing the working. Where a date depends on someone else (ethics approval, supervisor feedback, recruitment), mark it [EXTERNAL] and build in slack.
2. For each stage, key tasks, an editable estimate in weeks, and dependencies.
3. The critical path, in a sentence, and the three places the plan is most likely to slip.
4. A buffer of extra weeks for each risky stage, shown in its own column, with the reason.
5. If the plan does not fit before the deadline, say so plainly and offer three options for cutting scope or extending time, without pretending it fits.

Count in calendar weeks, say so, and subtract any holidays or leave I list under fixed commitments. Do not invent approvals, recruitment rates or processing times; ask me. Output as a table of milestones, then the risk list.