prd-to-plan

Convert a PRD into a phased implementation plan using vertical-slice tracer bullets. Break a PRD into a phased implementation plan using vertical slices (tracer bullets). Output is a Markdown file in ./plans/ . The PRD should already be in the conversation. If it isn't, ask the user to paste it or point you to the file. If you have not already explored the codebase, do so to understand the current architecture, existing patterns, and integration layers. Before slicing, identify high-level decisions that are unlikely to change throughout implementation: These go in the plan header so every phase can reference them. Break the PRD into tracer bullet phases.