fix: Correct HttpRequestBox method_id mapping in nyash.toml

Fixed the method ID order in HttpRequestBox configuration to match plugin implementation:
- path: method_id 1 (was incorrectly 2)
- readBody: method_id 2 (was incorrectly 3)
- respond: method_id 3 (was incorrectly 1)

This resolves the 45-day debugging issue where req.respond(resp) was calling
the wrong plugin method, causing HTTP responses to have empty bodies.

All E2E tests now pass:
- e2e_http_stub_end_to_end ✅
- e2e_http_multiple_requests_order ✅
- e2e_http_post_and_headers ✅
- e2e_http_server_restart ✅
- e2e_http_server_shutdown_and_restart ✅

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

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

src/box_trait.rs

@@ -109,6 +109,14 @@ pub trait NyashBox: BoxCore + Debug {
     /// Share this box (state-preserving reference sharing)
     fn share_box(&self) -> Box<dyn NyashBox>;
     
+    /// Identity hint: boxes that wrap external/stateful handles should override to return true.
+    fn is_identity(&self) -> bool { false }
+    
+    /// Helper: pick share or clone based on identity semantics.
+    fn clone_or_share(&self) -> Box<dyn NyashBox> {
+        if self.is_identity() { self.share_box() } else { self.clone_box() }
+    }
+    
     /// Arc参照を返す新しいcloneメソッド（参照共有）
     fn clone_arc(&self) -> SharedNyashBox {
         Arc::from(self.clone_box())
@@ -941,4 +949,4 @@ mod tests {
         assert_eq!(v.type_name(), "VoidBox");
         assert_eq!(v.to_string_box().value, "void");
     }
-}
+}