9aead397fd
Root cause: synth-diagnostic uses systemctl start to start pipeline services, but those services had After=synth-diagnostic — causing deadlock (they waited for synth-diagnostic to exit, which was waiting for them). Fix: pipeline services no longer list synth-diagnostic in After=. synth-diagnostic has Before= them for boot ordering, and starts them directly via systemctl start in run-tests.sh. Also fixed prometheus-exporter: had After=synth-diagnostic backwards — should start before synth-diagnostic (synth-diagnostic has After=prometheus-exporter).