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_simple_array.nyash

@@ -0,0 +1,27 @@
+// ArrayBox length問題の緊急調査
+static box ArrayDebugTest {
+    init { arr }
+    
+    main() {
+        print("=== ArrayBox緊急デバッグ ===")
+        
+        // ArrayBox作成
+        me.arr = new ArrayBox()
+        print("作成直後のlength: " + me.arr.length().toString())
+        
+        // 要素追加
+        me.arr.push("test1")
+        print("push後のlength: " + me.arr.length().toString())
+        
+        me.arr.push("test2")
+        print("2個目push後のlength: " + me.arr.length().toString())
+        
+        // 直接的なテスト
+        local newArr
+        newArr = new ArrayBox()
+        newArr.push("direct")
+        print("新しい配列のlength: " + newArr.length().toString())
+        
+        return "debug完了"
+    }
+}