Root cause: AISessionDetail.model_validate(session) tried to validate the
ORM relationship 'steps' which has field 'id', but AISessionStepResponse
expects 'step_id'. This caused a Pydantic ValidationError on every session
detail load.
Fix: Construct AISessionDetail manually from ORM fields, passing the
already-built step_responses list directly instead of relying on
model_validate to serialize the ORM steps relationship.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>