Task: Create backlog-refiner and sprint-planner skills and recipes

Produce two Claude Code skills (backlog-refiner, sprint-planner) and two companion agile recipes, so that both types of backlog session are structured, repeatable, and self-documenting.

• doc/llm/skills/backlog-refiner/SKILL.org exists and is a valid v2 skill doc.
• doc/llm/skills/sprint-planner/SKILL.org exists and is a valid v2 skill doc.
• doc/recipes/agile/how_do_i_refine_the_backlog.org exists and covers the full housekeeping checklist.
• doc/recipes/agile/how_do_i_plan_a_sprint.org exists and covers the goal-setting and selection workflow.
• .claude/skills/backlog-refiner.md and .claude/skills/sprint-planner.md are deployed (deploy_skills target passes).
• Site builds clean with all four new documents.

1. Scaffold backlog-refiner skill via generate_v2_doc.sh --type skill.
2. Scaffold sprint-planner skill via generate_v2_doc.sh --type skill.
3. Author both skills: when-to-use, how-to-use, step-by-step procedure.
4. Scaffold how_do_i_refine_the_backlog.org recipe via codegen.
5. Scaffold how_do_i_plan_a_sprint.org recipe via codegen.
6. Author both recipes: question, answer (checklist), script, tested-by, see-also.
7. Run deploy_skills and deploy_site to confirm clean build.