fix(store-and-forward): resolve S&F delivery + replication wiring (3 Critical findings)

Resolves StoreAndForward-001, ExternalSystemGateway-001, NotificationService-001
— one systemic gap where buffered messages were persisted but never delivered,
and the active node never replicated its buffer to the standby.

Delivery handlers (ExternalSystemGateway-001 / NotificationService-001):
- AkkaHostedService registers delivery handlers for the ExternalSystem,
  CachedDbWrite and Notification categories after StoreAndForwardService starts;
  each resolves its scoped consumer in a fresh DI scope.
- ExternalSystemClient, DatabaseGateway and NotificationDeliveryService each
  gain a DeliverBufferedAsync method: re-resolve the target and re-attempt
  delivery, returning true/false/throwing per the transient-vs-permanent contract.
- EnqueueAsync gains an attemptImmediateDelivery flag; CachedCallAsync and
  NotificationDeliveryService.SendAsync pass false (they already attempted
  delivery themselves) so registering a handler does not dispatch twice.

Replication (StoreAndForward-001):
- ReplicationService is injected into StoreAndForwardService; a new BufferAsync
  helper replicates every enqueue, and successful-retry removes and parks are
  replicated too. Fire-and-forget, no-op when replication is disabled.

Tests: StoreAndForwardReplicationTests (Add/Remove/Park observed),
attemptImmediateDelivery behaviour, and DeliverBufferedAsync paths for each
consumer. Full solution builds; StoreAndForward/ExternalSystemGateway/
NotificationService suites green.

code-reviews/README.md

@@ -34,11 +34,11 @@ resolved and re-triaged.
 
 | Severity | Open findings |
 |----------|---------------|
-| Critical | 3 |
+| Critical | 0 |
 | High | 46 |
 | Medium | 100 |
 | Low | 89 |
-| **Total** | **238** |
+| **Total** | **235** |
 
 ## Module Status
 
@@ -52,16 +52,16 @@ resolved and re-triaged.
 | [ConfigurationDatabase](ConfigurationDatabase/findings.md) | 2026-05-16 | `9c60592` | 0/1/4/6 | 11 | 11 |
 | [DataConnectionLayer](DataConnectionLayer/findings.md) | 2026-05-16 | `9c60592` | 0/4/6/2 | 12 | 13 |
 | [DeploymentManager](DeploymentManager/findings.md) | 2026-05-16 | `9c60592` | 0/3/6/5 | 14 | 14 |
-| [ExternalSystemGateway](ExternalSystemGateway/findings.md) | 2026-05-16 | `9c60592` | 1/2/7/4 | 14 | 14 |
+| [ExternalSystemGateway](ExternalSystemGateway/findings.md) | 2026-05-16 | `9c60592` | 0/2/7/4 | 13 | 14 |
 | [HealthMonitoring](HealthMonitoring/findings.md) | 2026-05-16 | `9c60592` | 0/2/5/5 | 12 | 12 |
 | [Host](Host/findings.md) | 2026-05-16 | `9c60592` | 0/1/3/7 | 11 | 11 |
 | [InboundAPI](InboundAPI/findings.md) | 2026-05-16 | `9c60592` | 0/3/5/5 | 13 | 13 |
 | [ManagementService](ManagementService/findings.md) | 2026-05-16 | `9c60592` | 0/3/5/5 | 13 | 13 |
-| [NotificationService](NotificationService/findings.md) | 2026-05-16 | `9c60592` | 1/3/5/3 | 12 | 12 |
+| [NotificationService](NotificationService/findings.md) | 2026-05-16 | `9c60592` | 0/3/5/3 | 11 | 12 |
 | [Security](Security/findings.md) | 2026-05-16 | `9c60592` | 0/3/4/4 | 11 | 11 |
 | [SiteEventLogging](SiteEventLogging/findings.md) | 2026-05-16 | `9c60592` | 0/4/4/3 | 11 | 11 |
 | [SiteRuntime](SiteRuntime/findings.md) | 2026-05-16 | `9c60592` | 0/3/8/5 | 16 | 16 |
-| [StoreAndForward](StoreAndForward/findings.md) | 2026-05-16 | `9c60592` | 1/2/4/6 | 13 | 13 |
+| [StoreAndForward](StoreAndForward/findings.md) | 2026-05-16 | `9c60592` | 0/2/4/6 | 12 | 13 |
 | [TemplateEngine](TemplateEngine/findings.md) | 2026-05-16 | `9c60592` | 0/5/5/4 | 14 | 14 |
 
 ## Pending Findings
@@ -71,13 +71,9 @@ Resolved findings drop off this list but remain recorded in their module's
 `findings.md` (see [REVIEW-PROCESS.md](REVIEW-PROCESS.md) §4–§5). Full detail —
 description, location, recommendation — lives in the module's `findings.md`.
 
-### Critical (3)
+### Critical (0)
 
-| ID | Module | Title |
-|----|--------|-------|
-| ExternalSystemGateway-001 | [ExternalSystemGateway](ExternalSystemGateway/findings.md) | No S&F delivery handler registered; cached calls and writes can never be delivered |
-| NotificationService-001 | [NotificationService](NotificationService/findings.md) | Buffered notifications are never retried (no S&F delivery handler) |
-| StoreAndForward-001 | [StoreAndForward](StoreAndForward/findings.md) | Replication to standby is never triggered by the active node |
+_None open._
 
 ### High (46)