improve examples: add basic/chunking/pool_completion, fix linter issues

- add basic example: minimal hello world for getting started
- add chunking example: demonstrates WithChunkFn for key-based routing
- add pool_completion example: shows pool completion callback usage
- add README.md for all new examples
- fix structural linter issues across all examples:
  - exitAfterDefer: use return instead of log.Fatal after defer
  - shadow: rename shadowed variables
  - intrange: use range over int (Go 1.22+)
  - modernize: use strings.FieldsSeq, interface{} -> any
  - prealloc: preallocate slices where size is known
- update examples/README.md with new examples

Hotfix release v0.8.1

- Fix: WithWorkerChanSize now properly recreates channels with configured size
- Fix: Remove duplicate comment in metrics.Stats.String
- Fix: Remove unnecessary context initialization in NewStateful
- Docs: Update minimum Go version requirement to 1.23+ (uses iter package)

Add rate limiter middleware

- Add RateLimiter middleware with token bucket algorithm
- Update to Go 1.24
- Migrate golangci-lint config to v2 format
- Fix batch overlap detection bug
- Improve test stability and documentation

switch to go 1.23

switch to go 1.24

Merge pull request #2 from go-pkgz/perf

Performance optimization

Add middleware support to pool package (#1)

* Add middleware support to pool package

Introduce middleware functionality to the pool package, enabling the addition of cross-cutting concerns like retries, timeouts, panic recovery, validation, metrics, and logging. Update README documentation with examples of built-in and custom middleware usage. Include comprehensive test cases

* lint: minor warns

* docs: update README to include middleware features

fix flaky test

lint: suppress false positive on magical numbers

Remove context-related configuration options from WorkerGroup

this is not needed anymore, as Go func accepts external context