/ultrareview fails with `firestore: not found` during seed bundle import (no remote, local-only repo)

Summary

/ultrareview consistently fails to start a remote session with a firestore: not found error during seed-bundle import. The failure happens before merge-base / diff-range computation — repeated retries, with and without arguments, all hit the same error.

Error (verbatim)

Ultrareview could not start the remote session: seed bundle: seed bundle import: failed to import files: error executing request: file not found: {"code":"not_found","message":"file to import not found: error retrieving file to import: firestore: not found"}

Reproduction

Local-only git repo (no remote). On a branch alpha02 containing ~41 commits.

/ultrareview              # fails
/ultrareview              # fails (retry)
/ultrareview <sha>        # fails (explicit base SHA)

All four invocations produced byte-identical errors, so it isn't transient load-balancing flakiness on the storage tier.

Environment / repo shape

• Local-only git repo, no remotes configured (git remote -v empty).
• Two branches:
• alpha02 — full history (~41 commits).
• main — single orphan commit (no shared ancestor with alpha02).
• Active branch: alpha02.

The orphan-main situation is what initially prevented merge-base from succeeding, but /ultrareview with no arguments uses the local-bundle path that shouldn't need merge-base — and the firestore: not found error suggests the bundle uploaded successfully but the server's lookup step failed afterward.

Expected

Either the seed bundle imports successfully, or the failure mode includes enough signal (e.g. retry-after, support reference id) to tell the user whether to retry or file a bug.

Actual

Hard failure on first attempt with no automatic retry; subsequent manual retries fail identically.