fix(cursor): update skill paths from .cursor/rules/ to .cursor/skills/

The Cursor Agent CLI now discovers skills from .cursor/skills/ instead
of the old .cursor/rules/ directory. Update all references across
create-plan and implement-plan Cursor variants and docs.

skills/create-plan/cursor/templates/continuation-runbook.md

@@ -16,7 +16,7 @@ Do NOT reference planner-private files during implementation.
 
 ## Skill Workflow Guardrails
 
-- Invoke relevant skills before action using workspace discovery (`.cursor/rules/`).
+- Invoke relevant skills before action using workspace discovery (`.cursor/skills/`).
 - Announce which skill is being used and why.
 - If a checklist-driven skill applies, track checklist execution explicitly.