Add tests for SBOM generation determinism across multiple formats

- Created `StellaOps.TestKit.Tests` project for unit tests related to determinism.
- Implemented `DeterminismManifestTests` to validate deterministic output for canonical bytes and strings, file read/write operations, and error handling for invalid schema versions.
- Added `SbomDeterminismTests` to ensure identical inputs produce consistent SBOMs across SPDX 3.0.1 and CycloneDX 1.6/1.7 formats, including parallel execution tests.
- Updated project references in `StellaOps.Integration.Determinism` to include the new determinism testing library.

docs2/observability-aoc.md

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+# AOC observability
+
+Purpose
+- Monitor Aggregation-Only ingestion for Concelier and Excititor.
+- Provide deterministic metrics, traces, and logs for AOC guardrails.
+
+Core metrics
+- ingestion_write_total{source,tenant,result}
+- ingestion_latency_seconds{source,tenant,phase}
+- aoc_violation_total{source,tenant,code}
+- ingestion_signature_verified_total{source,tenant,result}
+- advisory_revision_count{source,tenant}
+- verify_runs_total{tenant,initiator}
+- verify_duration_seconds{tenant,initiator}
+
+Alert guidance
+- Violation spike: increase(aoc_violation_total[15m]) > 0 for critical sources.
+- Stale ingestion: no growth in ingestion_write_total for > 60 minutes.
+- Signature drop: rising ingestion_signature_verified_total{result="fail"}.
+
+Health snapshot endpoint
+- GET /obs/excititor/health returns ingest, link, signature, conflict status.
+- Settings control warning and critical thresholds for lag, coverage, and conflict ratio.
+
+Trace taxonomy
+- ingest.fetch, ingest.transform, ingest.write
+- aoc.guard for violations
+- verify.run for verification jobs
+
+Log fields
+- traceId, tenant, source.vendor, upstream.upstreamId
+- contentHash, violation.code, verification.window
+- Correlation headers: X-Stella-TraceId, X-Stella-CorrelationId
+
+Advisory AI chunk metrics
+- advisory_ai_chunk_requests_total
+- advisory_ai_chunk_latency_milliseconds
+- advisory_ai_chunk_segments
+- advisory_ai_chunk_sources
+- advisory_ai_guardrail_blocks_total
+
+Dashboards
+- AOC ingestion health: sources overview, violations, signature rate, supersedes depth.
+- Offline mode dashboard from offline snapshots.
+
+Offline posture
+- Metrics exporters write to local Prometheus snapshots in offline kits.
+- CLI verification reports are hashed and archived.
+- Dashboards support offline data sources.