fix: add OTS instance endpoint fallback

[hhuangzhen]

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[Copilot]

Pull request overview

This PR updates OTS knowledge base retrieval to primarily use the instance-specific OTS endpoint and introduces a fallback to the legacy “frontend” endpoint when instance-endpoint retrieval fails (only in public/non-VPC mode).

Changes:

• Switch Config.get_ots_endpoint() (public mode) from the shared frontend domain to the instance-specific HTTPS endpoint.
• Add instance-endpoint failure fallback logic in OTSDataAPI.retrieve() / retrieve_async() (and corresponding template).
• Update and extend unit tests to validate the new endpoint selection and fallback behavior (sync + async).

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
agentrun/utils/config.py	Changes default (public) OTS endpoint construction to instance-specific https://{instance}.{region}.ots.aliyuncs.com.
agentrun/knowledgebase/api/__data_async_template.py	Adds OTS client override + fallback endpoint builder and fallback retry logic (template source for codegen).
agentrun/knowledgebase/api/data.py	Auto-generated output reflecting the template changes, including fallback behavior in OTS retrieval.
tests/unittests/utils/test_config.py	Updates expectations for the new default public OTS endpoint format.
tests/unittests/knowledgebase/test_ots_knowledgebase.py	Adds/updates tests to cover fallback behavior and updated endpoint usage for OTS client construction.

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