🔧 fix: FloatBoxインポートパス修正 + コンテキスト圧縮対策追加

- FloatBoxインポートをcrate::boxes::math_box::FloatBoxに修正
- expressions.rs, objects.rsでインポートパス統一
- CLAUDE.mdにコンテキスト圧縮時の重要ルール追加
- 次回Copilot作業のための準備完了

Note: FloatBox toString()はまだ未修正（Copilotに引き継ぎ）

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

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

src/interpreter/expressions.rs

@@ -8,7 +8,8 @@
 
 use super::*;
 use crate::ast::UnaryOperator;
-use crate::boxes::{buffer::BufferBox, JSONBox, HttpClientBox, StreamBox, RegexBox, IntentBox, P2PBox, FloatBox};
+use crate::boxes::{buffer::BufferBox, JSONBox, HttpClientBox, StreamBox, RegexBox, IntentBox, P2PBox};
+use crate::boxes::math_box::FloatBox;
 use crate::boxes::{MathBox, ConsoleBox, TimeBox, RandomBox, SoundBox, DebugBox, file::FileBox, MapBox};
 use crate::box_trait::BoolBox;
 use crate::operator_traits::OperatorResolver;