Add a workflow_dispatch workflow that loads the o11ybench agent observability
dataset into a fresh GreptimeDB container per cell and compares three WAL
configurations that differ only in [wal]: Raft Engine with sync_write on the
instance store, and the object store WAL in durable and enqueued mode, with
the data files on S3 in the runner's region for all three. Rounds alternate
the configuration order. A summary reports rows per second, D/R and E/R as
the geometric mean over rounds, append acknowledgement p50 and p99, and the
object store WAL counters. A smoke mode runs the same chain on ubuntu-latest
against the MinIO fixture.
Signed-off-by: jeremyhi <fengjiachun@gmail.com>