Recently came across a strange issue where Dolphin would hard crash in most games with this error:
```sh
/usr/include/c++/15.2.1/optional:1165: constexpr const _Tp* std::optional<_Tp>::operator->() const [with _Tp = InputCommon::ImagePixelData]: Assertion 'this->_M_is_engaged()' failed.
```
The culprit turned out to be accessing `host_key_image` which is an `std::optional` thay may return `std::nullopt`. I'm not sure why this issue started occuring for me since I've had no issue with my Dynamic Input Textures in the past? But this fixes a crash if the image fails to load.
In DITSpecification.cpp, MaterialAsset.cpp, and ShaderAsset.cpp, lambda predicates were replaced by pointers to member functions because ranges algorithms are able invoke those.
In NetPlayClient.cpp, the non-trivial `NetPlay::Player` elements were being passed by value in `NetPlayClient::DoAllPlayersHaveGame()`. This has been fixed.
In WIABlob.cpp, the second example's predicate was returning the `std::optional` by value instead of implicitly converting it to a bool. This has been fixed.
SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
