Include workflow ID in busy workflow errors

[kevinawoo]

What changed

• Added a workflow-ID-aware BusyWorkflow error wrapper that preserves the existing ErrResourceExhaustedBusyWorkflow sentinel via errors.Is.
• Returned that wrapper from workflow cache lock timeout paths when the workflow ID is known.
• Added tests covering the gRPC status message, ResourceExhausted cause/scope preservation, and the cache lock timeout return path.

Why

Generic BusyWorkflow responses currently return Workflow is busy. with no workflow identity. That makes the grpc_message useful for finding BusyWorkflow responses, but not for identifying the specific workflow execution. This keeps the existing BusyWorkflow cause/scope semantics while returning messages like:

Workflow is busy. WorkflowId: <workflow-id>.

Validation

• go test ./service/history/consts ./service/history/workflow/cache ./service/history/queues
• go test ./service/history -run TestDoesNotExist
• git diff --check