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/phase_9_78e_summary.md

@@ -1,5 +1,8 @@
 # Phase 9.78e: Dynamic Method Dispatch Implementation Summary
 
+> **Status**: Historical summary（Phase 9.78e 実装レポート）  
+> **Note**: 現在の設計・実装状況は最新の `docs/development/architecture/` / `docs/development/roadmap/` を正とし、このファイルは当時の実装状態の記録としてのみ参照してください。
+
 ## 🎯 Overview
 Phase 9.78e aimed to implement dynamic method dispatch through the `call_method` trait method to unify method calling across all Box types.
 
@@ -79,4 +82,4 @@ Phase 9.78e aimed to implement dynamic method dispatch through the `call_method`
 
 ---
 
-*Phase 9.78e establishes the foundation for unified method dispatch across all Nyash Box types, with the core infrastructure successfully implemented and ready for expanded integration.*
+*Phase 9.78e establishes the foundation for unified method dispatch across all Nyash Box types, with the core infrastructure successfully implemented and ready for expanded integration.*