🚀 feat: Phase 9.78b Step 1&2完了 - ChatGPT5による実装

ChatGPT5が実装したPhase 9.78b Step 1&2の統合

## 🎯 実装内容
1. Phase 9.78b Step 1: BoxDeclarationをcore::modelへ移動
   - src/core/mod.rs, model.rs 新規作成
   - BoxDeclarationを純粋データモデルとして分離

2. Phase 9.78b Step 2: NyashRuntime骨組み作成
   - src/runtime/nyash_runtime.rs 追加
   - 統一Box管理の基盤

3. ビルドエラー修正
   - Arc重複インポート修正
   - as_str() → as_ref() 変更
   - parent_name.to_string() 型変換
   - インポートパス調整

## 📊 ビルド結果
- ✅ フルビルド成功 (47.34秒)
- ✅ ユニットテスト: 145/145成功
- ✅ 統合テスト: 16/16成功
- ✅ WASMビルド成功 (1.9MB)
- ❌ MIRテスト: 1失敗 (ref_new命令)

## 🚀 次のステップ
- Phase 9.78b Step 3: BoxFactory dyn化
- Codexの設計に基づく段階的実装継続

src/runtime/mod.rs

@@ -6,6 +6,7 @@ pub mod plugin_config;
 pub mod box_registry;
 pub mod plugin_loader_v2;
 pub mod unified_registry;
+pub mod nyash_runtime;
 // pub mod plugin_box;  // legacy - 古いPluginBox
 // pub mod plugin_loader;  // legacy - Host VTable使用
 
@@ -16,6 +17,7 @@ pub use plugin_config::PluginConfig;
 pub use box_registry::{BoxFactoryRegistry, BoxProvider, get_global_registry};
 pub use plugin_loader_v2::{PluginLoaderV2, get_global_loader_v2, init_global_loader_v2};
 pub use unified_registry::{get_global_unified_registry, init_global_unified_registry, register_user_defined_factory};
+pub use nyash_runtime::{NyashRuntime, NyashRuntimeBuilder};
 // pub use plugin_box::PluginBox;  // legacy
 // Use unified plugin loader (formerly v2)
-// pub use plugin_loader::{PluginLoaderV2 as PluginLoader, get_global_loader_v2 as get_global_loader};  // legacy
+// pub use plugin_loader::{PluginLoaderV2 as PluginLoader, get_global_loader_v2 as get_global_loader};  // legacy

src/runtime/nyash_runtime.rs

@@ -0,0 +1,78 @@
+//! Minimal NyashRuntime skeleton shared by interpreter and VM
+//!
+//! Focused on dependency inversion: core models + runtime services,
+//! while execution strategies live in interpreter/VM layers.
+
+use std::collections::HashMap;
+use std::sync::{Arc, Mutex, RwLock};
+
+use crate::core::model::BoxDeclaration;
+use crate::box_factory::{UnifiedBoxRegistry, BoxFactory};
+use crate::box_factory::builtin::BuiltinBoxFactory;
+#[cfg(feature = "plugins")]
+use crate::box_factory::plugin::PluginBoxFactory;
+
+/// Core runtime container for executing Nyash programs
+pub struct NyashRuntime {
+    /// Unified registry that can create any Box type
+    pub box_registry: Arc<Mutex<UnifiedBoxRegistry>>,
+    /// User-defined box declarations collected from source
+    pub box_declarations: Arc<RwLock<HashMap<String, BoxDeclaration>>>,
+}
+
+impl NyashRuntime {
+    /// Create a new runtime with defaults
+    pub fn new() -> Self {
+        Self {
+            box_registry: create_default_registry(),
+            box_declarations: Arc::new(RwLock::new(HashMap::new())),
+        }
+    }
+}
+
+/// Builder for NyashRuntime allowing DI without globals (future-proof)
+pub struct NyashRuntimeBuilder {
+    box_registry: Option<Arc<Mutex<UnifiedBoxRegistry>>>,
+    box_declarations: Option<Arc<RwLock<HashMap<String, BoxDeclaration>>>>,
+}
+
+impl NyashRuntimeBuilder {
+    pub fn new() -> Self {
+        Self { box_registry: None, box_declarations: None }
+    }
+
+    /// Inject a BoxFactory implementation directly into a private registry
+    pub fn with_factory(mut self, factory: Arc<dyn BoxFactory>) -> Self {
+        let registry = self.box_registry.take().unwrap_or_else(|| create_default_registry());
+        if let Ok(mut reg) = registry.lock() {
+            reg.register(factory);
+        }
+        self.box_registry = Some(registry);
+        self
+    }
+
+    pub fn with_box_declarations(
+        mut self,
+        decls: Arc<RwLock<HashMap<String, BoxDeclaration>>>,
+    ) -> Self {
+        self.box_declarations = Some(decls);
+        self
+    }
+
+    pub fn build(self) -> NyashRuntime {
+        NyashRuntime {
+            box_registry: self.box_registry.unwrap_or_else(|| create_default_registry()),
+            box_declarations: self.box_declarations.unwrap_or_else(|| Arc::new(RwLock::new(HashMap::new()))),
+        }
+    }
+}
+
+fn create_default_registry() -> Arc<Mutex<UnifiedBoxRegistry>> {
+    let mut registry = UnifiedBoxRegistry::new();
+    registry.register(Arc::new(BuiltinBoxFactory::new()));
+    #[cfg(feature = "plugins")]
+    {
+        registry.register(Arc::new(PluginBoxFactory::new()));
+    }
+    Arc::new(Mutex::new(registry))
+}