Add determinism tests for verdict artifact generation and update SHA256 sums script

- Implemented comprehensive tests for verdict artifact generation to ensure deterministic outputs across various scenarios, including identical inputs, parallel execution, and change ordering.
- Created helper methods for generating sample verdict inputs and computing canonical hashes.
- Added tests to validate the stability of canonical hashes, proof spine ordering, and summary statistics.
- Introduced a new PowerShell script to update SHA256 sums for files, ensuring accurate hash generation and file integrity checks.

docs/airgap/prep/2025-11-20-controller-scaffold-prep.md

@@ -1,20 +0,0 @@
-# Controller Scaffold Prep — PREP-AIRGAP-CTL-56-001 / 56-002
-
-Status: Draft (2025-11-20)
-Owners: AirGap Controller Guild · DevOps Guild
-Scope: Provide the controller scaffold + status API contract so AIRGAP-CTL-56-001/56-002 can proceed.
-
-## Deliverables included
-- Service scaffold described in `docs/airgap/controller-scaffold.md` (project layout, DI wiring, config keys, auth scopes).
-- Baseline status/seal endpoints sketch:
-  - `GET /system/airgap/status` → `{sealed, policy_hash?, staleness_seconds?, time_anchor_id?, bundle_id?}`
-  - `POST /system/airgap/seal` (body: `{policy_hash, reason}`) → returns new state; requires `airgap:seal` scope.
-- Determinism & offline posture: no external calls; state persisted via `airgap_state` store; timestamps UTC; subject ordering deterministic.
-
-## Next steps for implementation
-- Generate controller project under `src/AirGap/StellaOps.AirGap.Controller` per scaffold.
-- Wire Authority scope checks (`airgap:seal`, `airgap:status:read`).
-- Add sealed-mode guard middleware and timeline events per `docs/airgap/sealed-startup-diagnostics.md` once integrated.
-
-## Handoff
-Use this prep doc to satisfy PREP-AIRGAP-CTL-56-001 and PREP-AIRGAP-CTL-56-002. Update if scope changes; otherwise move tasks to DONE.