Chris Tate 524af28870 Add fs read and write streams ...

fs.createReadStream, fs.createWriteStream and FileHandle
createReadStream, createWriteStream and readLines return runtime
Readable and Writable streams (scr_fs_stream.c), as do new fs.ReadStream
and new fs.WriteStream in JavaScript sources. They follow
lib/internal/fs/streams.js on the stream engine:

- _construct opens the file, then emits 'open' (with the fd) and
  'ready'; _read reads up to end; _write retries short writes as
  writeAll does; _destroy waits for I/O in flight, then closes (with
  fsync first for the flush option). Every open, read, write, fsync and
  close runs on the shared worker pool.
- Options are checked in Node's order: getOptions, options.fd or the
  path, start, end, then highWaterMark, encoding, emitClose and
  autoClose. flags and mode are checked when the file opens, so their
  errors arrive as 'error' events.
- bytesRead, bytesWritten, pending, path and close(cb) compile, also
  through untyped values (close() there).

A FileHandle stream holds a reference on the handle; closing the stream
releases it and closes the handle unless autoClose is false.
FileHandle.close() follows Node's reference count: it waits for the
streams over the handle and runs their close(). readLines is a readline
Interface over createReadStream with crlfDelay: Infinity.

The stream engine gains Node's _construct (reads, buffered writes,
finish and _destroy wait for construction; destroy errors combine with
aggregateTwoErrors) and _writev, both internal. Writable.destroy() now
runs the buffered write callbacks and end() callbacks (errorBuffer),
which it dropped before. highWaterMark in a dynamic options record is
checked as getHighWaterMark does, and for await over a constructing
stream waits for construction.

Numeric flags, the fs, signal and windowsHandle options, non-UTF-8
write encodings, option functions that replace the file implementation,
and instanceof fs.ReadStream/WriteStream are refused.

Corpus 5546, 5547 and 5554 cover both lanes against Node 24.22.

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docs

Add fs read and write streams

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limitations

Add fs read and write streams

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