Add integration tests for Proof Chain and Reachability workflows

- Implement ProofChainTestFixture for PostgreSQL-backed integration tests.
- Create StellaOps.Integration.ProofChain project with necessary dependencies.
- Add ReachabilityIntegrationTests to validate call graph extraction and reachability analysis.
- Introduce ReachabilityTestFixture for managing corpus and fixture paths.
- Establish StellaOps.Integration.Reachability project with required references.
- Develop UnknownsWorkflowTests to cover the unknowns lifecycle: detection, ranking, escalation, and resolution.
- Create StellaOps.Integration.Unknowns project with dependencies for unknowns workflow.

bench/golden-corpus/corpus-version.json

@@ -0,0 +1,15 @@
+{
+  "schema_version": "stellaops.corpus.version/v1",
+  "corpus_version": "1.0.0",
+  "scoring_algorithm_version": "v2.0",
+  "created_at": "2025-01-15T00:00:00Z",
+  "updated_at": "2025-01-15T00:00:00Z",
+  "openvex_schema": "0.2.0",
+  "spdx_version": "3.0.1",
+  "cyclonedx_version": "1.6",
+  "determinism_salt": "frozen-2025-01-15T00:00:00Z",
+  "compatibility": {
+    "min_stellaops_version": "0.9.0",
+    "max_stellaops_version": null
+  }
+}