feat: Prepare for code modularization and cleanup

- Archive old documentation and test files to `docs/archive/` and `local_tests/`.
- Remove various temporary and old files from the project root.
- Add `nekocode-rust` analysis tool and its output files (`nekocode/`, `.nekocode_sessions/`, `analysis.json`).
- Minor updates to `apps/chip8_nyash/chip8_emulator.nyash` and `local_tests` files.

This commit cleans up the repository and sets the stage for further code modularization efforts, particularly in the `src/interpreter` and `src/parser` modules, based on recent analysis.

local_tests/test_pack_transparency_final.nyash

@@ -0,0 +1,61 @@
+# 🔥 Phase 8.8: pack透明化システム 最終統合テスト
+# 全機能の協調動作確認
+
+print("=== pack透明化システム最終統合テスト開始 ===")
+
+# 1. 従来のbirth機能（ユーザー定義Box）
+box Animal {
+    init { name, species }
+    
+    birth(animalName, animalSpecies) {
+        me.name = animalName
+        me.species = animalSpecies
+    }
+    
+    introduce() {
+        return me.name + " は " + me.species + " です"
+    }
+}
+
+# 2. pack透明化（ビルトインBox継承）
+box SmartString from StringBox {
+    init { metadata }
+    
+    birth(content, meta) {
+        from StringBox(content)  # 透明化
+        me.metadata = meta
+    }
+    
+    getInfo() {
+        return "内容の情報: " + me.metadata
+    }
+}
+
+# 3. 複数のビルトインBox透明化
+box Calculator from MathBox {
+    init { precision }
+    
+    birth(precisionLevel) {
+        from MathBox.birth()  # Explicit syntax after Phase 8.9
+        me.precision = precisionLevel
+    }
+    
+    getPrecision() {
+        return "精度: " + me.precision
+    }
+}
+
+# テスト実行
+print("1. ユーザー定義Box:")
+local cat = new Animal("ミケ", "猫")
+print(cat.introduce())
+
+print("2. StringBox透明化:")
+local smartStr = new SmartString("Hello World", "UTF-8")
+print(smartStr.getInfo())
+
+print("3. MathBox透明化:")
+local calc = new Calculator("高精度")
+print(calc.getPrecision())
+
+print("=== 全テスト成功！pack透明化システム完了 ===")テム完了 ===")