feat: add perf module — OTel pipeline telemetry with Grafana dashboards
Add `perf` as the 12th skinny package with full OpenTelemetry
instrumentation for pipeline traces, Prometheus metrics, and
Loki-correlated logs.
- src/perf/: TracerProvider, MeterProvider, LoggerProvider bridge,
PipelineCollector, psutil system metrics, FileExporter fallback,
FastAPI middleware, auto-file Gitea issues on step/test failure
- infra/otel/: OTel Collector fan-out (traces→Jaeger, metrics→Prometheus,
logs→Loki), all services migrated from jaeger:4317 to collector
- infra/grafana/dashboards/: 8-panel pipeline performance dashboard
- Pipeline runner auto-instruments all 189 steps with zero-cost
MockTracer/MockSpan no-ops when telemetry is disabled
- 82 new tests, 12,055 total passing
Closes #203, closes #204, closes #205, closes #206, closes #207,
closes #208, closes #209, closes #210, closes #211, closes #212,
closes #213
7696c1c6da
