🔧 refactor: P2PBox複雑実装を削除し段階的実装方針に変更

- 複雑なP2PBox関連実装を削除:
  * Transport trait + MessageBus + MessageIntentBox + NewP2PBox
  * 依存関係が複雑で一度に追加すると失敗することを学習

- nyashバイナリのビルドを安定化:
  * 全てのimportエラーを修正
  * cargo build --bin nyash が正常に動作

- CURRENT_TASK.mdに新しい段階的実装方針を記載:
  * Phase 1: FloatBox (依存なし)
  * Phase 2: ArrayBox改良
  * Phase 3: 演算子システム改良

- 教訓: 一つずつ確実に実装し、テストファーストで進める

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

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

src/interpreter/expressions.rs

@@ -8,7 +8,7 @@
 
 use super::*;
 use crate::ast::UnaryOperator;
-use crate::boxes::{buffer::BufferBox, JSONBox, HttpClientBox, StreamBox, RegexBox, IntentBox, P2PBox, NewP2PBox, MessageIntentBox};
+use crate::boxes::{buffer::BufferBox, JSONBox, HttpClientBox, StreamBox, RegexBox, IntentBox, P2PBox};
 use crate::boxes::{MathBox, ConsoleBox, TimeBox, RandomBox, SoundBox, DebugBox, file::FileBox, MapBox};
 use crate::operator_traits::OperatorResolver;
 // TODO: Fix NullBox import issue later
@@ -747,7 +747,7 @@ impl NyashInterpreter {
             "TimeBox" | "DateTimeBox" | "TimerBox" | "RandomBox" | "SoundBox" | 
             "DebugBox" | "MethodBox" | "NullBox" | "ConsoleBox" | "FloatBox" |
             "BufferBox" | "RegexBox" | "JSONBox" | "StreamBox" | "HTTPClientBox" |
-            "IntentBox" | "P2PBox" | "NewP2PBox" | "MessageIntentBox" | "EguiBox"
+            "IntentBox" | "P2PBox" | "EguiBox"
         );
         
         if is_builtin {
@@ -941,26 +941,6 @@ impl NyashInterpreter {
                     message: format!("P2PBox delegation not yet fully implemented: {}.{}", parent, method),
                 });
             }
-            "NewP2PBox" => {
-                // NewP2PBoxの場合、current_instanceから実際のNewP2PBoxインスタンスを取得
-                if let Some(p2p_box) = current_instance.as_any().downcast_ref::<NewP2PBox>() {
-                    self.execute_new_p2p_box_method(p2p_box, method, arguments)
-                } else {
-                    Err(RuntimeError::TypeError {
-                        message: format!("Expected NewP2PBox instance for method call {}.{}", parent, method),
-                    })
-                }
-            }
-            "MessageIntentBox" => {
-                // MessageIntentBoxの場合、current_instanceから実際のMessageIntentBoxインスタンスを取得
-                if let Some(message_box) = current_instance.as_any_mut().downcast_mut::<MessageIntentBox>() {
-                    self.execute_message_intent_box_method(message_box, method, arguments)
-                } else {
-                    Err(RuntimeError::TypeError {
-                        message: format!("Expected MessageIntentBox instance for method call {}.{}", parent, method),
-                    })
-                }
-            }
             "FileBox" => {
                 let file_box = crate::boxes::file::FileBox::new();
                 self.execute_file_method(&file_box, method, arguments)