Implement Standalone Nexus Operations#1461

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VegetarianOrc wants to merge 9 commits intomainfrom

Commits on Apr 20, 2026

Make result_type take precedence in get_nexus_operation_handle to match start/execute operation. Fix hardcoded retryable=True in fallback error serialization. Add type tests and rename test/nexus/t…
VegetarianOrc
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Commits on Apr 22, 2026

Add caching of failures for NexusOperationHandle
VegetarianOrc
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Commits on Apr 23, 2026

Consistency pass on models from proto. Expose long_poll_token
VegetarianOrc
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Commits on Apr 24, 2026