feat: Add RustFS artifact object store and migration tool

- Implemented RustFsArtifactObjectStore for managing artifacts in RustFS.
- Added unit tests for RustFsArtifactObjectStore functionality.
- Created a RustFS migrator tool to transfer objects from S3 to RustFS.
- Introduced policy preview and report models for API integration.
- Added fixtures and tests for policy preview and report functionality.
- Included necessary metadata and scripts for cache_pkg package.

docs/12_PERFORMANCE_WORKBOOK.md

@@ -56,7 +56,7 @@
 ## 3 Test Harness
 
 * **Runner** – `perf/run.sh`, accepts `--phase` and `--samples`.  
-* **Language analyzers microbench** – `dotnet run --project bench/Scanner.Analyzers/StellaOps.Bench.ScannerAnalyzers/StellaOps.Bench.ScannerAnalyzers.csproj -- --repo-root . --out bench/Scanner.Analyzers/baseline.csv` produces deterministic CSVs for analyzer scenarios (Node today, others as they land).  
+* **Language analyzers microbench** – `dotnet run --project bench/Scanner.Analyzers/StellaOps.Bench.ScannerAnalyzers/StellaOps.Bench.ScannerAnalyzers.csproj -- --repo-root . --out bench/Scanner.Analyzers/baseline.csv --json out/bench/scanner-analyzers/latest.json --prom out/bench/scanner-analyzers/latest.prom --commit $(git rev-parse HEAD)` produces CSV + JSON + Prometheus gauges for analyzer scenarios. Runs fail if `max_ms` regresses ≥ 20 % against `baseline.csv` or if thresholds are exceeded.  
 * **Metrics** – Prometheus + `jq` extracts; aggregated via `scripts/aggregate.ts`.  
 * **CI** – GitLab CI job *benchmark* publishes JSON to `bench‑artifacts/`.  
 * **Visualisation** – Grafana dashboard *Stella‑Perf* (provisioned JSON).  
@@ -143,7 +143,9 @@ P99 = 48 ms. Meets 50 ms gate.
 
 ## 8 Trend Snapshot
 
-![Perf trend spark‑line placeholder](perf‑trend.svg)
+![Perf trend spark‑line placeholder](perf‑trend.svg)
+
+> **Grafana/Alerting** – Import `docs/ops/scanner-analyzers-grafana-dashboard.json` and point it at the Prometheus datasource storing `scanner_analyzer_bench_*` metrics. Configure an alert on `scanner_analyzer_bench_regression_ratio` ≥ 1.20 (default limit); the bundled Stat panel surfaces breached scenarios (non-zero values). On-call runbook: `docs/ops/scanner-analyzers-operations.md`.
 
 _Plot generated weekly by `scripts/update‑trend.py`; shows last 12 weeks P95 per phase._