Step 307: Go + C++ + Elisp parser deepening — struct/interface, class, template, lambda (12/12 tests)
Go: struct → ClassDeclaration, interface → InterfaceDeclaration, method receiver → MethodDeclaration, func literal → LambdaExpression, expression_list unwrapping
C++: class/struct → ClassDeclaration, template → TypeParameter, methods → MethodDeclaration, lambda_expression → LambdaExpression
Elisp: (lambda ...) special_form → LambdaExpression
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>