Verify the git backend's fold reads the durable log into CoordinationState with
unchanged semantics, and that read-your-writes holds across separate handles and
separate OS processes against the same space ref (one test spawns a real
subprocess that appends, then reads it back). Cross-process fold equals the
in-memory fold for the same event sequence (derived = f(log)).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
