Remove Task Manager implementation to match `# Setup module` in module.md.
Backend src/ reduced to Kernel.php + empty Entity/, all migrations deleted,
database dropped and recreated. Frontend components/views/services/stores
removed, App.vue/router/style.css reduced to skeletons. CLAUDE.md shortened
to Setup-stand. Old backend/plan.md, plan2.md removed.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
