feat: Implement Filesystem and MongoDB provenance writers for PackRun execution context

- Added `FilesystemPackRunProvenanceWriter` to write provenance manifests to the filesystem.
- Introduced `MongoPackRunArtifactReader` to read artifacts from MongoDB.
- Created `MongoPackRunProvenanceWriter` to store provenance manifests in MongoDB.
- Developed unit tests for filesystem and MongoDB provenance writers.
- Established `ITimelineEventStore` and `ITimelineIngestionService` interfaces for timeline event handling.
- Implemented `TimelineIngestionService` to validate and persist timeline events with hashing.
- Created PostgreSQL schema and migration scripts for timeline indexing.
- Added dependency injection support for timeline indexer services.
- Developed tests for timeline ingestion and schema validation.

docs/modules/export-center/operations/runbook.md

@@ -11,15 +11,16 @@ The Export Center packages StellaOps evidence and policy overlays into reproduci
 - Runbook execution for recovery, retention, and compliance.
 - Coordination with DevOps validation (cosign + `trivy module db import` smoke tests).
 
-Related documentation:
-
-- `docs/modules/export-center/overview.md`
-- `docs/modules/export-center/architecture.md`
-- `docs/modules/export-center/profiles.md`
-- `docs/modules/export-center/trivy-adapter.md`
-- `docs/modules/export-center/mirror-bundles.md`
-- `docs/modules/export-center/api.md`
-- `docs/modules/export-center/cli.md`
+Related documentation:
+
+- `docs/modules/export-center/overview.md`
+- `docs/modules/export-center/architecture.md`
+- `docs/modules/export-center/profiles.md`
+- `docs/modules/export-center/trivy-adapter.md`
+- `docs/modules/export-center/mirror-bundles.md`
+- `docs/modules/export-center/api.md`
+- `docs/modules/export-center/cli.md`
+- `docs/modules/export-center/operations/kms-envelope-pattern.md`
 
 ## 2. Contacts & tooling