docs: add ProcessMetrics section to README and fix rustdoc warnings

- Document ProcessMetrics and WorkerMetrics under a new
  "Process & worker metrics" section in the README
- Re-export WorkerState from lib.rs to resolve a private
  intra-doc link on WorkerMeta::state
- Fix broken [Pid] doc link in fetch_proess_metrics; the map
  is keyed by u32, not a Pid type
- Correct TimedMap::get doc comment; it returns Option<Arc<Mutex<V>>>,
  not a MutexGuard

chore: fix clippy lint in docs and export other struct from metrics

chore(deps): restore typed-emitter version.

Breaking change:support for shared-redis-connection across redis-store

instances

fix:logic bug in end-to-end benchmarks

false conditional used; worker stop running before running the work

chore(crates.io): limited the crate keywords to five(publish limit)

ci(cd-workflow): workflow should references to the old library versio…

…n in the readme

ci(cd): chose better category slugs for publishing crate