refactor: 大規模ファイル分割とプラグインリファクタリング

## 🎯 プラグイン整理
- ✅ **nyash-json-plugin**: プロバイダー抽象化、NodeRep統一
- ✅ **nyash-string-plugin**: TLVヘルパー整理
- ✅ **nyash-net-plugin**: HTTPヘルパー分離、ソケット管理改善
- ✅ **nyash-counter-plugin/fixture-plugin**: 基本構造整理

## 📂 mir_interpreter分割
- ✅ **mir_interpreter.rs → mir_interpreter/ディレクトリ**
  - mod.rs: メイン構造体定義
  - execution.rs: 実行エンジン
  - memory.rs: メモリ管理
  - instructions/: 命令別実装

## 🔧 その他の改善
- テストファイル群の最適化
- LLVMコンパイラのメイン関数整理
- 不要なインポート削除

1000行超のファイルを適切なモジュール構造に分割完了！

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

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

plugins/nyash-fixture-plugin/src/lib.rs

@@ -2,7 +2,10 @@
 
 use once_cell::sync::Lazy;
 use std::collections::HashMap;
-use std::sync::{atomic::{AtomicU32, Ordering}, Mutex};
+use std::sync::{
+    atomic::{AtomicU32, Ordering},
+    Mutex,
+};
 
 // ===== Error Codes (BID-1 alignment) =====
 const NYB_SUCCESS: i32 = 0;
@@ -42,7 +45,9 @@ pub extern "C" fn nyash_plugin_invoke(
     result: *mut u8,
     result_len: *mut usize,
 ) -> i32 {
-    if type_id != TYPE_ID_FIXTURE { return NYB_E_INVALID_TYPE; }
+    if type_id != TYPE_ID_FIXTURE {
+        return NYB_E_INVALID_TYPE;
+    }
     unsafe { dispatch(method_id, instance_id, args, args_len, result, result_len) }
 }
 
@@ -72,7 +77,9 @@ unsafe impl Sync for NyashTypeBoxFfi {}
 
 extern "C" fn fixture_resolve(name: *const std::os::raw::c_char) -> u32 {
     unsafe {
-        if name.is_null() { return 0; }
+        if name.is_null() {
+            return 0;
+        }
         let s = std::ffi::CStr::from_ptr(name).to_string_lossy();
         match s.as_ref() {
             "birth" => METHOD_BIRTH,
@@ -125,12 +132,18 @@ unsafe fn dispatch(
 }
 
 unsafe fn birth(result: *mut u8, result_len: *mut usize) -> i32 {
-    if result_len.is_null() { return NYB_E_INVALID_ARGS; }
-    if preflight(result, result_len, 4) { return NYB_E_SHORT_BUFFER; }
+    if result_len.is_null() {
+        return NYB_E_INVALID_ARGS;
+    }
+    if preflight(result, result_len, 4) {
+        return NYB_E_SHORT_BUFFER;
+    }
     let id = INSTANCE_COUNTER.fetch_add(1, Ordering::Relaxed);
     if let Ok(mut map) = INSTANCES.lock() {
         map.insert(id, FixtureInstance { alive: true });
-    } else { return NYB_E_PLUGIN_ERROR; }
+    } else {
+        return NYB_E_PLUGIN_ERROR;
+    }
     let bytes = id.to_le_bytes();
     std::ptr::copy_nonoverlapping(bytes.as_ptr(), result, 4);
     *result_len = 4;
@@ -141,33 +154,43 @@ unsafe fn fini(instance_id: u32) -> i32 {
     if let Ok(mut map) = INSTANCES.lock() {
         map.remove(&instance_id);
         NYB_SUCCESS
-    } else { NYB_E_PLUGIN_ERROR }
+    } else {
+        NYB_E_PLUGIN_ERROR
+    }
 }
 
-unsafe fn echo(
-    args: *const u8,
-    args_len: usize,
-    result: *mut u8,
-    result_len: *mut usize,
-) -> i32 {
+unsafe fn echo(args: *const u8, args_len: usize, result: *mut u8, result_len: *mut usize) -> i32 {
     // Expect TLV with 1 argument: tag=6 (String)
-    if args.is_null() || args_len < 4 { return NYB_E_INVALID_ARGS; }
+    if args.is_null() || args_len < 4 {
+        return NYB_E_INVALID_ARGS;
+    }
     let slice = std::slice::from_raw_parts(args, args_len);
     // Minimal TLV parse: skip header (ver/argc) and verify first entry is String
-    if slice.len() < 8 { return NYB_E_INVALID_ARGS; }
+    if slice.len() < 8 {
+        return NYB_E_INVALID_ARGS;
+    }
     if slice[0] != 1 || slice[1] != 0 { /* ver=1 little endian */ }
     // position 4.. is first entry; [tag, rsv, sz_lo, sz_hi, payload...]
     let tag = slice[4];
-    if tag != 6 { return NYB_E_INVALID_ARGS; }
+    if tag != 6 {
+        return NYB_E_INVALID_ARGS;
+    }
     let sz = u16::from_le_bytes([slice[6], slice[7]]) as usize;
-    if 8 + sz > slice.len() { return NYB_E_INVALID_ARGS; }
+    if 8 + sz > slice.len() {
+        return NYB_E_INVALID_ARGS;
+    }
     let payload = &slice[8..8 + sz];
-    let s = match std::str::from_utf8(payload) { Ok(t) => t, Err(_) => return NYB_E_INVALID_ARGS };
+    let s = match std::str::from_utf8(payload) {
+        Ok(t) => t,
+        Err(_) => return NYB_E_INVALID_ARGS,
+    };
     write_tlv_str(s, result, result_len)
 }
 
 fn write_tlv_result(payloads: &[(u8, &[u8])], result: *mut u8, result_len: *mut usize) -> i32 {
-    if result_len.is_null() { return NYB_E_INVALID_ARGS; }
+    if result_len.is_null() {
+        return NYB_E_INVALID_ARGS;
+    }
     let needed = 4 + payloads.iter().map(|(_, p)| 4 + p.len()).sum::<usize>();
     let mut buf: Vec<u8> = Vec::with_capacity(needed);
     buf.extend_from_slice(&1u16.to_le_bytes()); // ver
@@ -195,7 +218,9 @@ fn write_tlv_str(s: &str, result: *mut u8, result_len: *mut usize) -> i32 {
 
 fn preflight(result: *mut u8, result_len: *mut usize, needed: usize) -> bool {
     unsafe {
-        if result_len.is_null() { return false; }
+        if result_len.is_null() {
+            return false;
+        }
         if result.is_null() || *result_len < needed {
             *result_len = needed;
             return true;
@@ -203,4 +228,3 @@ fn preflight(result: *mut u8, result_len: *mut usize, needed: usize) -> bool {
     }
     false
 }
-