docs: Phase 114 DONE

Phase 114完了に伴うドキュメント更新:
- 30-Backlog.md: Phase 114の次候補から完了済みに移行
- design/control-tree.md: Phase 110-112の進捗反映
- design/README.md, joinir-design-map.md, phases/README.md: マイナー更新

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/development/current/main/design/README.md

@@ -9,3 +9,4 @@
 
 - JoinIR の地図（navigation SSOT）: `docs/development/current/main/design/joinir-design-map.md`
 - Loop Canonicalizer（設計 SSOT）: `docs/development/current/main/design/loop-canonicalizer.md`
+- ControlTree / StepTree（構造SSOT）: `docs/development/current/main/design/control-tree.md`