## What changed
- Capture optional `creator_user_id` and `creator_account_id` from authentication when creating a thread, including forks.
- Carry these fields through thread storage, rollout metadata, and a SQLite migration. Leave them absent when unavailable or when reading older threads.
- Preserve recorded creator values across resume and metadata updates. On revert, recover missing rollout values from SQLite before writing replacement metadata.
## Testing
Add coverage for ChatGPT and API-key sessions, resume under another account, forks using current authentication, metadata extraction and upserts, and repeated reverts after creator fields are removed from a rollout.
GitOrigin-RevId: 9839fa42f9392f12226002e2c27d05d5656f5695
