Restructure solution layout by module

src/Bench/StellaOps.Bench/PolicyEngine/README.md

@@ -0,0 +1,24 @@
+# Policy Engine Bench
+
+Synthetic workload that measures end-to-end policy evaluation throughput against large advisory snapshots.
+
+## Scenarios
+
+`config.json` defines the default scenario (`policy_eval_baseline`) which generates **100 000 components** with **1 000 000 findings** derived from deterministic seeds. The harness measures:
+
+- Latency (mean/p95/max milliseconds)
+- Throughput (findings per second)
+- Managed heap allocations (megabytes)
+
+## Running locally
+
+```bash
+dotnet run \
+  --project src/Bench/StellaOps.Bench/PolicyEngine/StellaOps.Bench.PolicyEngine/StellaOps.Bench.PolicyEngine.csproj \
+  -- \
+  --csv out/policy-bench.csv \
+  --json out/policy-bench.json \
+  --prometheus out/policy-bench.prom
+```
+
+The run exits non-zero if latency exceeds configured thresholds, throughput falls below the configured floor, or allocations surpass the budget. Baselines live in `baseline.csv` and can be regenerated whenever new steady-state metrics are established.