🚨 AI協調開発の危機回避事例を論文化（paper-09）

「ん？大丈夫？」の一言がPython特化ハードコーディングを防いだ事例を記録。
Everything is Box哲学 vs 技術的正しさの綱渡りからの生還を分析。

- docs/research/paper-09-ai-collaboration-pitfall/ を新規作成
  - incident-analysis.md: Lowerer特殊化危機の詳細分析
  - ai-collaboration-lessons.md: AI協調開発の教訓
  - intuition-in-engineering.md: エンジニアの直感の価値
  - summary.md: 綱渡りからの生還まとめ
- 研究論文の1論文1フォルダ原則に従い整理
- Python統合関連の実装修正とビルド成功確認

🛡️ Generated with Claude Code

src/runtime/unified_registry.rs

@@ -5,7 +5,7 @@
  * Integrates all Box creation sources (builtin, user-defined, plugin)
  */
 
-use crate::box_factory::{UnifiedBoxRegistry, builtin::BuiltinBoxFactory};
+use crate::box_factory::UnifiedBoxRegistry;
 #[cfg(feature = "plugins")]
 use crate::box_factory::plugin::PluginBoxFactory;
 use std::sync::{Arc, Mutex, OnceLock};
@@ -18,15 +18,7 @@ pub fn init_global_unified_registry() {
     GLOBAL_REGISTRY.get_or_init(|| {
         let mut registry = UnifiedBoxRegistry::new();
         
-        // Register built-in Box factory (highest priority) unless disabled
-        let disable_builtins = std::env::var("NYASH_DISABLE_BUILTINS").ok().as_deref() == Some("1");
-        if !disable_builtins {
-            registry.register(Arc::new(BuiltinBoxFactory::new()));
-        } else {
-            eprintln!("[UnifiedRegistry] Builtin boxes disabled via NYASH_DISABLE_BUILTINS=1");
-        }
-        
-        // Register plugin Box factory (lowest priority)
+        // Register plugin Box factory (primary)
         #[cfg(feature = "plugins")]
         {
             registry.register(Arc::new(PluginBoxFactory::new()));