Changed is_valid_pk() from sync to async to properly wait for file
creation without blocking. This is a breaking change but we're in
active development.
Changes:
- is_valid_pk() signature: fn -> async fn
- Replaced std:🧵:sleep with tokio::time::sleep
- Updated all 6 call sites in pmoplaylist to add .await:
- WriteHandle::push()
- WriteHandle::push_set()
- ReadHandle::pop()
- ReadHandle::peek()
- ReadHandle::remaining()
- ReadHandle::get_all()
Benefits:
- Non-blocking wait for file creation during ingestion
- More idiomatic async Rust code
- Better integration with tokio runtime