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/status/phase24-verification-report.md

@@ -1,5 +1,8 @@
 # Phase 2.4 Verification Report
 
+> **Status**: Historical verification report（アーカイブ候補）  
+> **Note**: 本レポートは Phase 2.4 完了時点の検証記録です。現行状態の確認には `docs/development/status/` の他レポートや最新の roadmap を参照してください。
+
 > **Generated**: 2025-09-24
 > **Status**: ✅ Successfully Verified
 > **Context**: Post-legacy cleanup verification after 151MB reduction
@@ -127,4 +130,4 @@ Phase 2.4 objectives achieved:
 
 **Signed off by**: Claude (AI Assistant)
 **Date**: 2025-09-24
-**Next Phase**: 15.5 "Everything is Plugin"
+**Next Phase**: 15.5 "Everything is Plugin"