Problem:
- "process" is often used as a verb (`multiqueue_process_events`), which
is ambiguous for cases where it's used as a topic.
- The documented naming convention for processes is "proc".
- `:help dev-name-common`
- Shorter is better, when it doesn't harm readability or
discoverability.
Solution:
Rename "process" => "proc" in all C symbols and module names.
