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_array2.nyash

@@ -0,0 +1,10 @@
+// 更にシンプルなArrayBoxテスト
+local arr
+arr = new ArrayBox()
+print("初期length: " + arr.length().toString())
+
+arr.push("item1")
+print("push後length: " + arr.length().toString())
+
+arr.push("item2")  
+print("2つ目push後length: " + arr.length().toString())