feat(file): add Reader method for streaming file access

ref

pool rate

 refactor(pool): replace parallel iterators with CancelOn predicate a…

…nd Stream improvements

  Remove all parallel iterator types (SeqSlicePar, SeqDequePar, SeqHeapPar, SeqMapPar) and
  their Parallel() methods in favor of Pool-based concurrency. Add CancelOn(predicate) for
  flexible pool cancellation beyond just errors, add FromResultChan for converting Stream
  channels to SeqResult iterators, add SuccessfulTasks() counter, simplify Wait(), and
  recover panics in Stream's producer goroutine.

feat: add With/RWith scoped lock methods and Pool.Stream mode

- Mutex.With and RwLock.With/RWith eliminate manual Lock/Unlock
  management with automatic scoped access
- Pool.Stream returns a channel emitting results in real-time
  using a fixed worker pool instead of accumulating all results
- Add Float.Gte/Lte comparison methods
- Simplify Set.Clear (builtin clear) and MapSafe.IsEmpty (atomic counter)

feat(result): add Wrap method for error context chaining

feat(result): add ErrIs, ErrAs, and ErrSource methods

 Add error inspection methods analogous to the errors package:
 - ErrIs: check if error matches target (errors.Is)
 - ErrAs: cast error to specific type (errors.As)
 - ErrSource: get wrapped error as Option[error] (errors.Unwrap)

readme

fix(MapSafe): fix race conditions in SafeEntry API and add atomic Len…

… counter

feat(option): add JSON marshal/unmarshal support; fix PathSeparator typo