Add MongoDB storage library and update acceptance tests with deterministic stubs

- Created StellaOps.Notify.Storage.Mongo project with initial configuration.
- Added expected output files for acceptance tests (at1.txt to at10.txt).
- Added fixture input files for acceptance tests (at1 to at10).
- Created input and signature files for test cases fc1 to fc5.

docs/vuln/explorer-overview.md

@@ -36,6 +36,16 @@
 3) Expose via API/Console/CLI with cached reachability/VEX context and policy explain bundles (VEX-first, reachability second, policy gates third per architecture).
 4) Export reports/offline bundles; verify with ledger hashes and DSSE attestations.
 
+## Triage States (architecture; finalize with GRAP0101)
+- `new` → `triaged` → `in_progress` → `awaiting_verification` → `remediated`
+- `new` → `closed_false_positive`
+- `new` → `accepted_risk`
+- Each transition requires justification; accepted risk requires multi-approver workflow (Policy Studio) and ABAC enforcement.
+
+## Offline / Export Expectations
+- Offline bundle structure: `manifest.json`, `findings.jsonl`, `history.jsonl`, `actions.jsonl`, `reports/`, `signatures/` (DSSE envelopes); deterministic ordering and hashes.
+- Bundles are consumed by Export Center mirror profiles; include Merkle roots and hash manifests for verification.
+
 ## Offline/Determinism Notes
 - Hash captures for screenshots/payloads recorded in `docs/assets/vuln-explorer/SHA256SUMS` (empty until assets arrive).
 - Use fixed fixture sets and ordered outputs when adding examples.