Host node awareness

**Describe the feature**
NTH v2 should be aware of which node it's running on so that it can optimise the workflow for cordon/drain of that node, ideally so it exits cleanly.

**Is the feature request related to a problem?**
NTH will terminate itself leaving errors in the logs.

**Describe alternatives you've considered**
n/a

No files, tests, or entry points are named. Start by tracing the NTH v2 node termination workflow, especially cordon/drain handling, and determine how host-node awareness should support a clean exit; done means the handler avoids leaving errors when terminating on its own node.

Written by the indexing model from the issue text.