{AKS}: fix BlockingIOError by setting stdout to non-blocking

[mainred]

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[Copilot]

Pull request overview

This PR fixes a BlockingIOError that occurs when writing to a full pipe buffer on macOS, and improves connection error handling for the AKS agent extension. The version is bumped from 1.0.0b13 to 1.0.0b14.

Key Changes:

• Implemented chunked writing for stdout with retry logic to handle BlockingIOError when pipe buffers are full
• Added helper functions for terminal mode management, error detection, and proper cleanup
• Enhanced signal handling and resource cleanup with a centralized cleanup function

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 14 comments.

File	Description
src/aks-agent/setup.py	Version bump to 1.0.0b14
src/aks-agent/HISTORY.rst	Added release notes for version 1.0.0b14 documenting the fixes
src/aks-agent/azext_aks_agent/agent/k8s/pod_exec.py	Major refactoring: added terminal mode helpers, centralized cleanup, chunked stdout writing with BlockingIOError handling, improved error detection, and Windows console UTF-8 configuration

Comments suppressed due to low confidence (1)

src/aks-agent/azext_aks_agent/agent/k8s/pod_exec.py:453

• stderr handling uses sys.stderr.write() which can also encounter BlockingIOError on full pipe buffers, but it lacks the chunking and error handling that stdout has (lines 429-447). For consistency and to prevent similar blocking issues, stderr should use the same chunked writing approach with os.write().

                # Handle stderr
                if resp.peek_stderr():
                    stderr_data = resp.read_stderr()
                    sys.stderr.write(stderr_data)
                    sys.stderr.flush()

[gossion]

lgtm

[yanzhudd]

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[Release] Update index.json for extension [ aks-agent-1.0.0b14 ] : https://dev.azure.com/msazure/One/_build/results?buildId=147198073&view=results