validation_error implicit copy/move constructor

We had a number of program options , most `uint*_t` and one additional that is a `vector` using `mutlitoken` ) that began erroring. This was working, but post updates to boost 1.88.0 (prior 1.75.0) + clang 19.1.7, it now produces an error. We have opted to throw some push/pops around this in our code right now to suppress the issue but would like to address it with a more appropriate fix. Included below is the warning for one of the numeric options. We did not investigate these as much as we did the arguments_map ( https://github.com/boostorg/program_options/issues/146 ), but would believe this one is better handled by adding default constructors (this might even be a case where `BOOST_DEFAULTED_FUNCTION` should be updated) as nothing jumps out as being a pointer where special handling may be required but would like those with more knowledge of the library to weigh in.

```
In file included from /home/user/bitbucket/app/build/_deps/boost-src/libs/program_options/include/boost/program_options.hpp:15:
In file included from /home/user/bitbucket/app/build/_deps/boost-src/libs/program_options/include/boost/program_options/options_description.hpp:12:
/home/user/bitbucket/app/build/_deps/boost-src/libs/program_options/include/boost/program_options/errors.hpp:383:34: error: definition of implicit copy constructor for 'validation_error' is deprecated because it has a user-declared destructor [-Werror,-Wdeprecated-copy-with-dtor]
383 | BOOST_DEFAULTED_FUNCTION(~validation_error() BOOST_NOEXCEPT_OR_NOTHROW, {})
| ^
/home/user/bitbucket/app/build/_deps/boost-src/libs/throw_exception/include/boost/throw_exception.hpp:97:41: note: in implicit copy constructor for 'boost::program_options::validation_error' first required here
97 | explicit wrapexcept( E const & e ): E( e )
| ^
/home/user/bitbucket/app/build/_deps/boost-src/libs/throw_exception/include/boost/throw_exception.hpp:165:11: note: in instantiation of member function 'boost::wrapexcept::wrapexcept' requested here
165 | throw wrapexcept( e );
| ^
/home/user/bitbucket/app/build/_deps/boost-src/libs/program_options/include/boost/program_options/detail/value_semantic.hpp:62:24: note: in instantiation of function template specialization 'boost::throw_exception' requested here
62 | boost::throw_exception(validation_error(validation_error::multiple_values_not_allowed));
| ^
/home/user/bitbucket/app/build/_deps/boost-src/libs/program_options/include/boost/program_options/detail/value_semantic.hpp:90:48: note: in instantiation of function template specialization 'boost::program_options::validators::get_single_string' requested here
90 | std::basic_string s(validators::get_single_string(xs));
| ^
/home/user/bitbucket/app/build/_deps/boost-src/libs/program_options/include/boost/program_options/detail/value_semantic.hpp:184:13: note: in instantiation of function template specialization 'boost::program_options::validate' requested here
184 | validate(value_store, new_tokens, static_cast(nullptr), 0);
| ^
/home/user/bitbucket/app/build/_deps/boost-src/libs/program_options/include/boost/program_options/value_semantic.hpp:189:9: note: in instantiation of member function 'boost::program_options::typed_value::xparse' requested here
189 | typed_value(T* store_to)
| ^
/home/user/bitbucket/app/build/_deps/boost-src/libs/program_options/include/boost/program_options/detail/value_semantic.hpp:199:33: note: in instantiation of member function 'boost::program_options::typed_value::typed_value' requested here
199 | typed_value* r = new typed_value(v);
| ^
/home/user/bitbucket/app/apps/app_name/src/main.cpp:111:49: note: in instantiation of function template specialization 'boost::program_options::value' requested here
111 | ("listen_port", boost::program_options::value(&opt_listen_port)->value_name("LISTEN_PORT")->required(),"Port to listen on")
| ^
```

https://quuxplusone.github.io/blog/2023/05/05/deprecated-copy-with-dtor/
https://stackoverflow.com/a/51864979

从 errors.hpp 中的 validation_error 开始，检查其析构函数和特殊成员函数如何与 BOOST_DEFAULTED_FUNCTION 交互。然后详细跟踪 throw_exception.hpp 中的复制构造，以及 detail/value_semantic.hpp 中的调用路径。完成的标准是解决报告的 deprecated-copy-with-dtor 错误，而不需要调用方抑制诊断。

由索引模型根据 Issue 内容生成。