Move edit-prd workflow and steps-e/ out of the shared create-prd directory
into its own bmad-edit-prd skill directory with SKILL.md, workflow.md, and
bmad-skill-manifest.yaml. Update pm.agent.yaml and module-help.csv to use
skill:bmad-edit-prd. Fix validationWorkflow path in step-e-04 to use
absolute {project-root} reference since relative path breaks after move.
Alex Verkhovsky