Honor requested WebSocket protocol in muxed pod exec

[Copilot]

MuxedStreamNamespacedPodExecAsync ignored the requested WebSocket subprotocol, opening V4 even when callers selected V5.

• Option forwarding: Pass the subprotocol, stream flags, and custom headers to WebSocketNamespacedPodExecAsync.
• V5 support: Enable channel-close support when the negotiated protocol is V5 binary; retain V4 as the default.
• Regression coverage: Cover protocol selection, negotiated-protocol handling, and option forwarding.

using var demuxer = await client.MuxedStreamNamespacedPodExecAsync(
    podName,
    namespaceName,
    command: new[] { "/bin/sh" },
    webSocketSubProtocol: WebSocketProtocol.V5BinaryWebsocketProtocol);

• Fixes MuxedStreamNamespacedPodExecAsync doesn't open a V5 WebSocket #1946

[Copilot]

Copilot wasn't able to review any files in this pull request. Check if the Files changed in this pull request are included in default exclusions.

[linux-foundation-easycla]

• ✅ login: brendandburns / name: Brendan Burns (5103b96)
• ❌ - login: @copilot / name: copilot-swe-agent[bot]. The commit (5103b96, 85619bb) is not authorized under a signed CLA. Please click here to be authorized. For further assistance with EasyCLA, please visit our EasyCLA portal and chat with our support bot.

[kubernetes-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Copilot
Once this PR has been reviewed and has the lgtm label, please ask for approval from brendandburns. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[Copilot]

🟢 Approval recommended

The focused fix preserves V4 defaults and includes regression coverage, with no blocking issues identified; tests were not executed during this review.

0 open findings

🧠 Review effort: Balanced