fix(otel): preserve operation start status

[zhongkechen]

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Issue Link, if available

N/A

Description

• Add nullable status to OperationInfo, matching the Python and TypeScript plugin contracts.
• Populate operation status from checkpointed operations while preserving the existing constructor for compatibility.
• Set invocation-view operation spans from OperationInfo.status, falling back to STARTED only when status is unavailable.
• Add regression coverage for STARTED, supplied statuses, and terminal status replacement.

Demo/Screenshots

N/A

Checklist

• I have filled out every section of the PR template
• I have thoroughly tested this change

Testing

Unit Tests

Yes. Added converter and invocation OTel plugin assertions for null, non-null, and terminal operation statuses.

Integration Tests

Existing integration tests pass as part of the full repository suite:

JAVA_HOME=/Library/Java/JavaVirtualMachines/amazon-corretto-17.jdk/Contents/Home mvn test

Examples

N/A; no example behavior or public workflow API changed.