Add unit tests for SBOM ingestion and transformation

- Implement `SbomIngestServiceCollectionExtensionsTests` to verify the SBOM ingestion pipeline exports snapshots correctly.
- Create `SbomIngestTransformerTests` to ensure the transformation produces expected nodes and edges, including deduplication of license nodes and normalization of timestamps.
- Add `SbomSnapshotExporterTests` to test the export functionality for manifest, adjacency, nodes, and edges.
- Introduce `VexOverlayTransformerTests` to validate the transformation of VEX nodes and edges.
- Set up project file for the test project with necessary dependencies and configurations.
- Include JSON fixture files for testing purposes.

samples/api/scheduler/policy-simulation-metrics.json

@@ -0,0 +1,17 @@
+{
+  "policy_simulation_queue_depth": {
+    "total": 3,
+    "by_status": {
+      "pending": 2,
+      "dispatching": 1
+    }
+  },
+  "policy_simulation_latency": {
+    "samples": 2,
+    "p50_seconds": 1.5,
+    "p90_seconds": 2.5,
+    "p95_seconds": 3.5,
+    "p99_seconds": 4.0,
+    "mean_seconds": 2.0
+  }
+}