fix(lib): genesis-only offline save must not rewind the outbox forever

[joepio]

Related Issues

Unbreaks develop full Playwright after #1301. The quoting fix let the suite run; this is the actual test failure:

https://github.com/ontola/atomic-server/actions/runs/32518361794

offline-create-then-online failed all 3 attempts:

waitForSynced timed out. pendingDirtyCount: 1, syncInProgress: true, hasSignedGenesis: false

Cause

saveOffline stored the local genesis cursor as a rewind baseVersion. The comment already said to skip that when nothing had been server-acked; the code did not.

On reconnect the drain POSTed genesis, then the empty follow-up export looked like "OPFS not ready" and the outbox retried forever. The default ontology of an extra drive is genesis-only, so it was the stranded entry.

Fix

• Do not set baseVersion when a signedGenesis is still unposted.
• If this drain pass POSTed genesis and the follow-up export is empty, clear the dirty bit.

Covered by browser/lib/src/offline-create-drain.test.ts. Commit is tagged [full-e2e] so this PR runs the same suite that failed on develop.

Checklist

• Add or update tests if needed
• Update docs if needed (TESTING_COVERAGE.md)