fix(kosong): classify base openai.APIError as retryable for streaming disconnections

[RealKai42]

Summary

• When the OpenAI SDK encounters a mid-stream transport failure, it raises the base openai.APIError (not APIConnectionError). The existing convert_error() did not handle this case — the error fell through to a generic ChatProviderError, bypassing both _run_with_connection_recovery and tenacity retry logic, causing an unrecoverable crash.
• Added a guarded case openai.APIError() branch with dual guards (type(error) is openai.APIError + error.body is None) that heuristically maps transport-layer errors to the appropriate retryable error type based on message content.
• SSE semantic errors (with body) and APIResponseValidationError subclasses are explicitly excluded from the heuristic classification.

Test plan

• 13 parametrized unit tests covering network/timeout pattern matching, negative cases (bare "reset"/"closed"), and timeout-over-network priority
• 2 safety guard tests: SSE error with body skips heuristic; APIResponseValidationError falls through
• 1 subclass priority regression test
• 1 streaming integration test: mock mid-flight APIError("Network connection lost.") → APIConnectionError
• make check-kosong passes (0 new diagnostics)
• Full kosong test suite: 69 passed

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[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.

[Copilot]

Pull request overview

This PR fixes an unrecoverable crash in the Kosong OpenAI integration when the OpenAI SDK raises a base openai.APIError during mid-stream transport failures (notably streaming disconnections), by classifying those base errors as retryable so existing recovery/retry logic can run.

Changes:

• Extend convert_error() to detect exact openai.APIError instances with body is None and heuristically map them to APIConnectionError / APITimeoutError.
• Add unit + integration tests covering the new base-APIError classification behavior and guardrails (body-present SSE errors and validation errors should not be reclassified).
• Document the fix in package and CLI release notes / changelogs.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
packages/kosong/src/kosong/chat_provider/openai_common.py	Adds guarded base openai.APIError handling and message-based heuristic classification for retryability.
packages/kosong/tests/test_openai_common.py	Adds parametrized unit tests and a streaming integration test to prevent regression.
packages/kosong/CHANGELOG.md	Notes the Kosong package-level fix in Unreleased.
CHANGELOG.md	Notes the CLI-level fix in Unreleased.
docs/en/release-notes/changelog.md	Adds the Unreleased release-note entry in English.
docs/zh/release-notes/changelog.md	Adds the Unreleased release-note entry in Chinese.

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