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/attestor/operations/dashboards/attestor-observability.json

@@ -0,0 +1,6 @@
+{
+  "_note": "Placeholder Grafana dashboard stub for Attestor. Replace panels when metrics endpoints are available; keep offline-import friendly.",
+  "schemaVersion": 39,
+  "title": "Attestor Observability (stub)",
+  "panels": []
+}

docs/modules/attestor/operations/observability.md

@@ -0,0 +1,39 @@
+# Attestor observability runbook (stub · 2025-11-29 demo)
+
+## Dashboards (offline import)
+- Grafana JSON: `docs/modules/attestor/operations/dashboards/attestor-observability.json` (import locally; no external data sources assumed).
+- Planned panels: signing latency p95/p99, verification failure rate, transparency log submission lag, key rotation age, DSSE verification errors, queue depth/backlog, and attestation bundle size histogram.
+
+## Key metrics
+- `attestor_sign_latency_seconds_bucket` — signing latency per request.
+- `attestor_verify_failures_total{reason}` — verification failures.
+- `attestor_tlog_submission_latency_seconds_bucket` — transparency log latency.
+- `attestor_key_rotation_age_seconds` — time since last rotation.
+- `attestor_queue_backlog` — pending attestation jobs.
+- `attestor_bundle_size_bytes_bucket` — bundle size distribution.
+
+## Logs & traces
+- Correlate by `correlationId`, `attestationId`, `tenant`, `keyId`. Include `policyVersion`, `tlogIndex`, and `rekorUrl` where applicable.
+- Traces disabled by default for air-gap; enable by pointing OTLP exporter to on-prem collector.
+
+## Health/diagnostics
+- `/health/liveness` and `/health/readiness` check signer availability, tlog reachability, and storage.
+- `/status` exposes build version, commit, feature flags; verify against offline bundle manifest.
+- Verification probe: `POST /api/attestations/verify` with sample bundle once demo outputs land.
+
+## Alert hints
+- Signing latency p99 > 1s.
+- Verification failure spikes.
+- Transparency log submission lag > 10s.
+- Key rotation age exceeding policy threshold.
+- Queue backlog above configured threshold.
+
+## Offline verification steps
+1) Import Grafana JSON locally; point to Prometheus scrape labeled `attestor`.
+2) Run sample verification once demo bundle available and confirm metrics/logs emit locally.
+3) Fetch `/status` and compare commit/version to offline bundle manifest.
+
+## Evidence locations
+- Sprint tracker: `docs/implplan/SPRINT_0313_0001_0001_docs_modules_attestor.md`.
+- Module docs: `README.md`, `architecture.md`, `implementation_plan.md`.
+- Dashboard stub: `operations/dashboards/attestor-observability.json`.