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/modules/router/messaging-valkey-transport.md

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+# Router · Messaging Transport over Valkey (Draft v0.1)
+
+## Status
+- Draft; intended for implementation via a dedicated sprint.
+- Last updated: 2025-12-23 (UTC).
+
+## Purpose
+Enable Gateway ↔ microservice Router traffic over an offline-friendly, Redis-compatible transport (Valkey) by using the existing **Messaging** transport layer:
+- Router transport: `StellaOps.Router.Transport.Messaging`
+- Messaging backend: `StellaOps.Messaging.Transport.Valkey`
+
+This supports environments where direct TCP/TLS microservice connections are undesirable, and where an internal message bus is the preferred control plane.
+
+## What Exists Today (Repository Reality)
+- Messaging transport server/client:
+  - `src/__Libraries/StellaOps.Router.Transport.Messaging/MessagingTransportServer.cs`
+  - `src/__Libraries/StellaOps.Router.Transport.Messaging/MessagingTransportClient.cs`
+- Valkey-backed message queue factory:
+  - `src/__Libraries/StellaOps.Messaging.Transport.Valkey/ValkeyMessageQueueFactory.cs`
+- Gateway WebService currently starts only TCP/TLS transport servers:
+  - `src/Gateway/StellaOps.Gateway.WebService/Program.cs`
+  - `src/Gateway/StellaOps.Gateway.WebService/Services/GatewayHostedService.cs`
+
+## High-Level Flow
+1) Microservice connects via messaging transport:
+   - publishes a HELLO message to the gateway request queue
+2) Gateway processes HELLO:
+   - registers instance + endpoints into routing state
+3) Gateway routes an HTTP request to a microservice:
+   - publishes a REQUEST message to the service request queue
+4) Microservice handles request:
+   - executes handler (or ASP.NET bridge) and publishes a RESPONSE message
+5) Gateway returns response to the client.
+
+## Queue Topology (Conceptual)
+The Messaging transport uses a small set of queues (names are configurable):
+- **Gateway request queue**: receives HELLO / HEARTBEAT / REQUEST frames from services
+- **Gateway response queue**: receives RESPONSE frames from services
+- **Per-service request queues**: gateway publishes REQUEST frames targeted to a service
+- **Dead letter queues** (optional): for messages that exceed retries/leases
+
+## Configuration (Draft)
+### Gateway
+- Register Valkey messaging services (`StellaOps.Messaging.Transport.Valkey`)
+- Add messaging transport server (`AddMessagingTransportServer`)
+- Add Gateway config section for messaging transport options:
+  - Valkey connection info (host/port/auth)
+  - queue naming prefix
+  - consumer group / lease duration / dead-letter suffix
+
+### Microservice
+- Register Valkey messaging services (`StellaOps.Messaging.Transport.Valkey`)
+- Add messaging transport client (`AddMessagingTransportClient`)
+- Ensure Microservice Router SDK connects via `IMicroserviceTransport`
+
+## Operational Semantics (Draft)
+- **At-least-once** delivery: message queues and leases imply retries are possible; handlers should be idempotent where feasible.
+- **Lease timeouts**: must be tuned to max handler execution time; long-running tasks should respond with 202 + job id rather than blocking.
+- **Determinism**: message ordering may vary; Router must not depend on arrival order for correctness (only for freshness/telemetry).
+
+## Security Notes
+- Messaging transport is internal. External identity must still be enforced at the Gateway.
+- The Gateway must not trust client-supplied identity headers; it must overwrite reserved headers before dispatch.
+  - See `docs/modules/gateway/identity-header-policy.md`.
+
+## Gaps / Implementation Work
+1) Wire Messaging transport into Gateway:
+   - start/stop `MessagingTransportServer`
+   - subscribe to HELLO/HEARTBEAT/RESPONSE events and reuse existing HELLO validation + routing state updates
+2) Extend Gateway transport client to support `TransportType.Messaging` for dispatch.
+3) Add config mapping and deployment examples (compose/helm) for Valkey transport.
+4) Add integration tests covering:
+   - microservice HELLO registration via messaging
+   - request dispatch + response return
+