## Summary
This updates Pregel callback manager initialization to pass
`tracerInheritableMetadata` defaults derived from `config.configurable`,
and narrows `ensureLangGraphConfig` metadata mirroring to the
allowlisted LangGraph identifiers used in stream/runtime metadata.
## Changes
### `@langchain/langgraph` (`libs/langgraph-core`)
- Updated Pregel callback manager setup to configure core callbacks with
`tracerInheritableMetadata` based on configurable primitive values,
excluding internal and secret-like keys.
- Hoisted tracing default logic into `_getTracingMetadataDefaults` and
`_excludeAsMetadata` for parity with the Python implementation shape.
- Restricted `ensureLangGraphConfig` configurable-to-metadata
propagation to the identifier allowlist:
- `thread_id`
- `checkpoint_id`
- `checkpoint_ns`
- `task_id`
- `run_id`
- `assistant_id`
- `graph_id`
- Updated config tests to assert the narrowed metadata propagation
behavior.
Hunter Lovell