Epic: benchmark campaigns — land the `bench-campaign` pipeline as reviewable units

[marwen-abid]

TL;DR

The bench-campaign pipeline works: one workflow_dispatch launches a fresh EC2 box, runs the full ingest and query suite against a target commit, waits across four relay windows, publishes the run to the results site (https://stellar-experimental.github.io/stellar-rpc-benchmarks) and posts a Slack card. The three accepted Phase 1/2/3 runs of 2026-09-10 came from it.

The code that produced those runs is not on any mainline.