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.

src/__Libraries/StellaOps.Replay.Core/AGENTS.md

@@ -0,0 +1,20 @@
+# StellaOps.Replay.Core — Agent Charter
+
+## Purpose
+Own shared replay domain types, canonicalisation helpers, bundle hashing utilities, and DSSE payload builders that power deterministic replay across Stella Ops services.
+
+## Required Reading
+- `docs/replay/DETERMINISTIC_REPLAY.md`
+- `docs/replay/DEVS_GUIDE_REPLAY.md`
+- `docs/modules/platform/architecture-overview.md` (Replay CAS section once published)
+- `docs/data/replay_schema.md` (when created)
+
+## Expectations
+1. Maintain deterministic behaviour (lexicographic ordering, canonical JSON, fixed encodings).
+2. Keep APIs offline-friendly; no network dependencies.
+3. Coordinate schema and bundle changes with Scanner, Evidence Locker, CLI, and Docs guilds.
+4. Update module `TASKS.md` statuses alongside `docs/implplan/SPRINT_185_replay_core.md`.
+
+## Contacts
+- BE-Base Platform Guild (primary)
+- Docs Guild (for spec alignment)

src/__Libraries/StellaOps.Replay.Core/TASKS.md

@@ -0,0 +1,6 @@
+# StellaOps.Replay.Core — Task Board
+
+| ID | Status | Description | Dependencies | Exit Criteria |
+|----|--------|-------------|--------------|---------------|
+| REPLAY-CORE-185-001 | TODO | Scaffold replay core library (`StellaOps.Replay.Core`) with manifest schema types, canonical JSON utilities, Merkle helpers, DSSE payload builders, and module charter updates referencing `docs/replay/DETERMINISTIC_REPLAY.md`. | Sprint 185 replay planning | Library builds/tests succeed; AGENTS.md updated; integration notes cross-linked. |
+| REPLAY-CORE-185-002 | TODO | Implement deterministic bundle writer (tar.zst, CAS naming) and hashing abstractions; extend `docs/modules/platform/architecture-overview.md` with “Replay CAS” section. | REPLAY-CORE-185-001 | Bundle writer unit tests pass; documentation merged with examples; CAS layout reproducible. |