fix(logging): add missing process_type ostream operator<<

[watilde]

This PR adds a required operator<< overload for the process_type enum, which is necessary for logging with ada_log. If there is a more appropriate or recommended way to handle this, please let me know!

Steps to reproduce:

cmake -B build -DADA_TESTING=ON
cmake --build build 
ADA_LOGGING=1 ctest --output-on-failure --test-dir build