feat: MIR Call命令統一Phase 3.1-3.2完了！統一Call実装進行中

✨ Phase 3.1-3.2実装完了
- build_indirect_call_expressionでCallTarget::Value使用
- print関数をcall_global print()として統一
- build_function_callでemit_unified_call使用
- ExternCall(env.console.log)→Callee::Global(print)完全移行

🏗️ MIR統一基盤構築
- src/mir/definitions/call_unified.rs: 統一定義（297行）
- emit_unified_call()と便利メソッド3種実装
- NYASH_MIR_UNIFIED_CALL=1で段階移行制御
- VM実行器でCallee対応実装済み

📊 進捗状況（26%削減見込み）
- Phase 1-2: ✅ 基盤構築完了
- Phase 3.1-3.2: ✅ 基本関数統一完了
- Phase 3.3: 🔄 BoxCall統一中
- Phase 4: 📅 Python LLVM（最優先・63%削減）
- Phase 5: 📅 PyVM/VM統一

📚 ドキュメント更新
- CLAUDE.md: テストスクリプト参考集追加
- CURRENT_TASK.md: Phase 3進捗更新
- python-llvm-priority-rationale.md: 優先順位戦略文書化
- mir-call-unification-master-plan.md: スケジュール最新化

🎯 6種類→1種類: Call/BoxCall/PluginInvoke/ExternCall/NewBox/NewClosure → MirCall統一へ

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

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

docs/development/current/function_values_and_captures.md

@@ -27,4 +27,4 @@ MIR/VM call unification (Phase 12)
   - If the callee is a String, VM performs a named-function dispatch (existing path).
   - If the callee is a `FunctionBox` (BoxRef), VM runs it via the interpreter helper with captures/`me` injected and proper return propagation.
 - Lambda immediate calls are still directly lowered inline for P1 compatibility.
-- Lambda→FunctionBox: Lambda expressions now lower to a `FunctionNew` MIR instruction that constructs a `FunctionBox` value (minimal: captures currently omitted). This enables MIR-only pipelines to construct and call function values.
+- Lambda→FunctionBox: Lambda expressions now lower to a `NewClosure` MIR instruction that constructs a `FunctionBox` value (minimal: captures currently omitted). This enables MIR-only pipelines to construct and call function values.