- Replace WorkerPool-based pipelines with typed `Pipe` abstraction in obipipeline
- Introduce Pipe/PipeIter for composable, sourceless/sink-less pipelines
- Update partition and superkmer commands to use new Pipe API via make_pipe!
- Remove Arc<Mutex<...>> patterns; simplify state management
- Fix macOS available_memory() returning 0 by falling back to half total memory in dereplicate()
- Remove unused `format: "zstd"` field from partition.meta