Proposal: Add review stage to workflow.md

What

Update the Feature Request Lifecycle section in workflow.md to include the review stage and its transition rules.

Why

The workflow documentation must match the actual lifecycle. The new review stage creates a clear handoff point where Opus considers work complete and the user verifies before marking done.

Spec

Change 1 — Update the lifecycle flow line.

Replace:

01_ideas/ → 02_new/ → 03_planned/ → 04_in-progress/ → 05_done/

With:

01_ideas/ → 02_new/ → 03_planned/ → 04_in-progress/ → 05_review/ → 06_done/

Change 2 — Update the transition rules.

Replace:

- **In Progress → Done**: mark phases done, move file, update feature-dashboard.

With:

- **In Progress → Review**: all phases complete, move file to `05_review/`, update feature-dashboard. User reviews.
- **Review → Done**: user verifies and approves. Move file to `06_done/`.

Impact

Only vault/00_system/docs/workflow.md is affected. Defines new transition rules that skills and agents will follow when moving feature requests through the lifecycle.