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/orchestrator/architecture.md

@@ -38,8 +38,9 @@
 - `POST /api/limits/throttle` — apply throttle (requires elevated scope).
 - `GET /api/dashboard/metrics` — aggregated metrics for Console dashboards.
 - Event envelope draft (`docs/modules/orchestrator/event-envelope.md`) defines notifier/webhook/SSE payloads with idempotency keys, provenance, and task runner metadata for job/pack-run events.
-
-All responses include deterministic timestamps, job digests, and DSSE signature fields for offline reconciliation.
+- OpenAPI discovery: `/.well-known/openapi` exposes `/openapi/orchestrator.json` (OAS 3.1) with pagination/idempotency/error-envelope examples; legacy job detail/summary endpoints now ship `Deprecation` + `Link` headers that point to their replacements.
+
+All responses include deterministic timestamps, job digests, and DSSE signature fields for offline reconciliation.
 
 ## 5) Observability