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_errors.nyash

@@ -0,0 +1,20 @@
+# 🔥 Phase 8.8: pack透明化システム エラーケーステスト
+# 適切なエラーメッセージとpackの隠蔽確認
+
+print("=== pack透明化システム エラーケーステスト開始 ===")
+
+# テスト1: 引数不一致エラー
+box BadStringBox from StringBox {
+    init { prefix }
+    
+    birth(content, extra) {
+        # StringBoxは1引数だが2つ渡すとエラー
+        from StringBox(content, extra)
+        me.prefix = "test"
+    }
+}
+
+print("エラーテスト1: 引数不一致")
+local bad = new BadStringBox("hello", "extra")
+
+print("=== pack透明化システム エラーケーステスト完了 ===")