fix: preserve triage conversation links

[oz-for-oss]

Closes #426

Summary

• Persist Oz session/conversation links into cloud run state when cron polling sees them.
• Restore the persisted link when reconstructing progress comments for terminal result application.
• Preserve terminal-run session links as a fallback for run adapters and add focused tests for final triage link propagation.

Validation

• python -m unittest tests.test_handlers tests.test_workflow_adapters
• python -m py_compile core/workflow_adapters.py oz/agent_workflow.py tests/test_handlers.py tests/test_workflow_adapters.py

Notes

• Full repository validation could not be completed in this image because pytest, pip, and runtime dependencies including github, yaml, and oz_agent_sdk are unavailable.