feat(hako_check): Phase 153 - Dead code detection revival (JoinIR version)

Implement comprehensive dead code detection for hako_check with JoinIR
integration, following Phase 133/134/152 box-based modularity pattern.

## Key Achievements

1. **Comprehensive Inventory** (`phase153_hako_check_inventory.md`):
   - Documented current hako_check architecture (872 lines)
   - Analyzed existing HC011/HC012 rules
   - Confirmed JoinIR-only pipeline (Phase 124)
   - Identified Phase 153 opportunities

2. **DeadCodeAnalyzerBox** (`rule_dead_code.hako`):
   - Unified HC019 rule (570+ lines)
   - Method-level + box-level dead code detection
   - DFS reachability from entrypoints
   - Text-based analysis (no MIR JSON dependency for MVP)
   - Heuristic-based false positive reduction

3. **CLI Integration** (`cli.hako`):
   - Added `--dead-code` flag for comprehensive mode
   - Added `--rules dead_code` for selective execution
   - Compatible with --format (text/json-lsp/dot)

4. **Test Infrastructure**:
   - HC019_dead_code test directory (ng/ok/expected.json)
   - `hako_check_deadcode_smoke.sh` with 4 test cases

## Technical Details

- **Input**: Analysis IR (MapBox with methods/calls/boxes/entrypoints)
- **Output**: HC019 diagnostics
- **Algorithm**: Graph-based DFS reachability
- **Pattern**: Box-based modular architecture
- **No ENV vars**: CLI flags only

## Files Modified

- NEW: docs/development/current/main/phase153_hako_check_inventory.md
- NEW: tools/hako_check/rules/rule_dead_code.hako
- MOD: tools/hako_check/cli.hako
- NEW: tools/hako_check/tests/HC019_dead_code/
- NEW: tools/hako_check_deadcode_smoke.sh
- MOD: CURRENT_TASK.md

## Next Steps

- Phase 154+: MIR CFG integration for block-level detection
- Phase 160+: Integration with .hako JoinIR/MIR migration

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

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

docs/development/current/CURRENT_VM_CHANGES.md

@@ -1,5 +1,8 @@
 # 🔄 現在のVM変更状態 (2025-08-21)
 
+> **Status**: Legacy snapshot（Phase 9.78 系の記録）  
+> **Note**: 現在の正本はリポジトリ直下の `CURRENT_TASK.md` および `docs/development/roadmap/` / `docs/private/roadmap/` 側に集約しています。このファイルは当時の実装状況メモとしてのみ残しています。
+
 ## 📊 Phase 9.78a VM統一Box処理の実装状況
 
 ### ✅ 完了したステップ
@@ -144,4 +147,4 @@ VM → UnifiedBoxRegistry ✅ (推奨)
 
 ---
 
-**結論**: **Option A（置いておく）**を推奨します。現在の実装は方向性として正しく、インタープリター整理後に続きから再開するのが最も効率的です。
+**結論**: **Option A（置いておく）**を推奨します。現在の実装は方向性として正しく、インタープリター整理後に続きから再開するのが最も効率的です。