Fix custom $stderrEvent for container attach and logs streams

[clue]

This changeset fixes the custom $stderrEvent for containerAttachStream() and containerLogsStream(). Both methods first inspect the container to check its TTY setting and previously returned a stream that only forwarded data, end, error and close events, so the custom STDERR event never reached the caller. The stream now forwards this event as well. This has been broken since both methods were added in #53 (2019) and #61 (2020), and the functional tests now cover both against a real Docker daemon.

Builds on top of #107, #61 and #53
Resolves / closes #96

[Copilot]

🟡 Changes recommended

Custom event names matching lifecycle events can cause argument errors or duplicate error notifications.

1 open issue

• Avoid duplicate or invalid forwarding of stderr lifecycle events · New

What changed in this PR

Fixes custom STDERR event forwarding for container attach and log streams, addressing #96.

Changes:

• Forwards custom events through the internal stream wrapper.
• Passes the event name from both client methods.
• Adds unit and Docker-backed functional regression tests.

File	Description
tests/​Io/​ReadableUnwrapStreamTest.php	Tests custom forwarding and avoids duplicate data events.
tests/​FunctionalClientTest.php	Checks STDERR delivery against Docker.
tests/​ClientTest.php	Tests custom events from both client methods.
src/​Io/​ReadableUnwrapStream.php	Adds optional custom event forwarding.
src/​Client.php	Passes STDERR event names to the wrapper.

_{Review effort: Balanced}