feat(types): add CxOne stubs so conv.cxone resolves in projects

[JaySonani]

Summary

Companion to genai_lambda_runtime#116, which adds conv.cxone for NICE CXone Signal API handoffs. Without these stubs conv.cxone doesn't exist in _gen, so builders get no autocomplete and a project function that catches CxOneSignalError fails its local tests.

Adds cxone.py to STUB_FILES, the generated src/poly/types/cxone.py, and the cxone property on the Conversation stub.

Deliberately not a full resync

Scoped to the CXone delta rather than running sync_runtime_stubs.py wholesale, because a full resync is currently broken:

STUB_FILES is missing clock.py, knowledge_base.py and verified_context.py, but the current runtime conversation.py imports all three. A full run therefore emits a conversation.py stub importing three modules that never get generated — the resulting _gen package raises ModuleNotFoundError on import, which would break every project. That's pre-existing and worth fixing, but not in a CXone change. Happy to raise it separately.

(A full run also picks up genuine additive drift that's accumulated since the last sync — AgenticDial.unsubscribe_from_destination, XaiVoice/GradiumVoice, BackgroundTrack, Attachment.chart_spec, EntityValidationResult.details, new prompt_llm models. All safe, all missing from the committed stubs, all better handled in a dedicated resync PR once the three missing modules are added.)

Circular-import note

runtime/cxone.py deliberately does not import Conversation, not even under TYPE_CHECKING. The generator promotes TYPE_CHECKING imports to unconditional ones, and conversation.py imports CxOne, so the pair would be circular and _gen unimportable. flow.py uses the same annotate-against-Conversation pattern safely only because nothing imports flow back. There's a comment on the runtime side so nobody re-adds it.

Testing

• Verified the generated package actually imports and resolves, rather than just eyeballing the stub:

  _gen imported OK
  CxOne exports: ['CxOne', 'CxOneError', 'CxOneMissingContactId', 'CxOneSecretError', 'CxOneSignalError', 'CxOneTokenError']
  Conversation.cxone is a property: True
  CxOne attrs: ['handoff', 'signal', 'contact_id', 'default_secret_name']
  cxone -> return annotation: <class '_gen.cxone.CxOne'>
  

• 1352 passed, 112 subtests passed
• ruff check / ruff format --check clean

Ticket

https://poly-ai.atlassian.net/browse/HSP-16548

🤖 Generated with Claude Code

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Coverage Report

Base (main)	PR	Change
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