revert: 古いプラグインシステム実装前の状態に巻き戻し

- ソースコードをcommit 3f7d71fの状態に復元（古いプラグインシステム実装前）
- docsフォルダは最新の状態を維持（BID-FFI設計ドキュメント含む）
- nyashバイナリの基本動作確認済み
- BID-FFIシステムをクリーンに再実装する準備完了

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

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

src/interpreter/methods/io_methods.rs

@@ -10,64 +10,11 @@
 use super::super::*;
 use crate::box_trait::{ResultBox, StringBox, NyashBox};
 use crate::boxes::FileBox;
-#[cfg(feature = "dynamic-file")]
-use crate::interpreter::plugin_loader::FileBoxProxy;
 
 impl NyashInterpreter {
     /// FileBoxのメソッド呼び出しを実行
     /// Handles file I/O operations including read, write, exists, delete, and copy
     pub(in crate::interpreter) fn execute_file_method(&mut self, file_box: &FileBox, method: &str, arguments: &[ASTNode]) 
-        -> Result<Box<dyn NyashBox>, RuntimeError> {
-        self.execute_file_method_static(file_box, method, arguments)
-    }
-    
-    /// FileBoxProxyのメソッド呼び出しを実行（動的ライブラリ版）
-    #[cfg(feature = "dynamic-file")]
-    pub(in crate::interpreter) fn execute_file_proxy_method(&mut self, file_box: &FileBoxProxy, method: &str, arguments: &[ASTNode]) 
-        -> Result<Box<dyn NyashBox>, RuntimeError> {
-        eprintln!("🔍 DEBUG: execute_file_proxy_method called with method: '{}'", method);
-        match method {
-            "read" => {
-                if !arguments.is_empty() {
-                    return Err(RuntimeError::InvalidOperation {
-                        message: format!("read() expects 0 arguments, got {}", arguments.len()),
-                    });
-                }
-                file_box.read()
-            }
-            "write" => {
-                if arguments.len() != 1 {
-                    return Err(RuntimeError::InvalidOperation {
-                        message: format!("write() expects 1 argument, got {}", arguments.len()),
-                    });
-                }
-                let content = self.execute_expression(&arguments[0])?;
-                file_box.write(content)
-            }
-            "exists" => {
-                if !arguments.is_empty() {
-                    return Err(RuntimeError::InvalidOperation {
-                        message: format!("exists() expects 0 arguments, got {}", arguments.len()),
-                    });
-                }
-                file_box.exists()
-            }
-            "toString" => {
-                if !arguments.is_empty() {
-                    return Err(RuntimeError::InvalidOperation {
-                        message: format!("toString() expects 0 arguments, got {}", arguments.len()),
-                    });
-                }
-                Ok(Box::new(file_box.to_string_box()))
-            }
-            _ => Err(RuntimeError::InvalidOperation {
-                message: format!("Undefined method '{}' for FileBox", method),
-            }),
-        }
-    }
-    
-    /// 静的FileBoxのメソッド実装
-    fn execute_file_method_static(&mut self, file_box: &FileBox, method: &str, arguments: &[ASTNode]) 
         -> Result<Box<dyn NyashBox>, RuntimeError> {
         match method {
             "read" => {
@@ -118,14 +65,6 @@ impl NyashInterpreter {
                     })
                 }
             }
-            "toString" => {
-                if !arguments.is_empty() {
-                    return Err(RuntimeError::InvalidOperation {
-                        message: format!("toString() expects 0 arguments, got {}", arguments.len()),
-                    });
-                }
-                Ok(Box::new(file_box.to_string_box()))
-            }
             _ => Err(RuntimeError::InvalidOperation {
                 message: format!("Unknown method '{}' for FileBox", method),
             })

src/interpreter/methods/mod.rs

@@ -23,6 +23,5 @@ pub mod data_methods;       // BufferBox, JSONBox, RegexBox
 pub mod network_methods;    // HttpClientBox, StreamBox
 pub mod p2p_methods;        // IntentBox, P2PBox
 pub mod http_methods;       // SocketBox, HTTPServerBox, HTTPRequestBox, HTTPResponseBox
-pub mod math_methods;       // MathBox, RandomBox, TimeBox, DateTimeBox
 
 // Re-export methods for easy access