Stage-Gate Milestone Plan for a Waterfall Project

Act as a project manager in an organization that uses stage gates. Build a milestone plan the steering group can approve.

Project phases and their main deliverables: {{PHASE_DELIVERABLES}}
Dates already fixed (contractual, regulatory, launch events): {{FIXED_DATES}}
Our governance: who approves each gate and how often they meet: {{GOVERNANCE}}

Produce:
1. A milestone table: milestone | phase | definition of done (the evidence that proves it) | gate approver | target date (only dates I gave you; otherwise [DATE TBD]).
2. Gate criteria for each stage: four to six questions the approver should be able to answer yes to before work moves on.
3. Where the governance calendar could delay a gate (for example, a board that meets monthly), with a suggested workaround such as a pre-booked slot or delegated approval.
4. A one-paragraph summary to put at the top of the plan.

Rules: milestones are zero-duration events, not activities. Write them as completed states ("Design signed off"), not tasks ("Design work"). Don't invent dates or durations. If a gate has no clear approver in my inputs, say so. Where a phase has no deliverable that proves it is finished, flag the phase and suggest what evidence would.