Method as_or

src/fl/stl/json.h:650–653

    // This method uses try_as<T>() for proper string-to-number conversion
    template<typename T>
    T as_or(const T& fallback) const FL_NOEXCEPT {
        auto result = try_as<T>();
        return result.has_value() ? *result : fallback;
    }

    // has_value method for compatibility
    bool has_value() const FL_NOEXCEPT {