Task 178: Mark analysis.relativistic-effects as valid in DAG

Status: DONE

Description

Task 177 completed the relativistic effects assessment and added it to the cross-episode report (commit ee4ba30), but the DAG node analysis.relativistic-effects was left as pending. It should be valid since the analysis is done.

The node is already correctly listed as a dependency of report.cross_episode (line 1052 of dag/state.json).

Actions

1. Set analysis.relativistic-effects status to valid in dag/state.json
2. Add appropriate metadata (tags, lastValidated, version)
3. Update DAG seed snapshot
4. Run tests to verify