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.

out/release/debug/debug-manifest.json

@@ -0,0 +1,13 @@
+{
+  "generatedAt": "2025-11-03T21:56:23Z",
+  "artifacts": [
+    {
+      "buildId": "0000000000000000000000000000000000000000",
+      "platform": "linux/amd64",
+      "kind": "elf-debug",
+      "debugPath": "debug/dummy.debug",
+      "sha256": "eff2b4e47e7a104171a2be80d6d4a5bce2a13dc33f382e90781a531aa926599a",
+      "size": 26
+    }
+  ]
+}

out/release/debug/debug-manifest.json.sha256

@@ -0,0 +1 @@
+d924d25e7b028105a1c7d16cb1d82955edf103a48571a253b474d8ee30a1b577  debug-manifest.json

out/release/debug/dummy.debug

@@ -0,0 +1 @@
+portable-debug-placeholder