feat: wire SQLite replication between site nodes and fix ConfigurationDatabase tests

Add SiteReplicationActor (runs on every site node) to replicate deployed
configs and store-and-forward buffer operations to the standby peer via
cluster member discovery and fire-and-forget Tell. Wire ReplicationService
handler and pass replication actor to DeploymentManagerActor singleton.

Fix 5 pre-existing ConfigurationDatabase test failures: RowVersion NOT NULL
on SQLite, stale migration name assertion, and seed data count mismatch.

src/ScadaLink.DeploymentManager/FlatteningPipeline.cs

@@ -83,8 +83,18 @@ public class FlatteningPipeline : IFlatteningPipeline
 
         var config = flattenResult.Value;
 
+        // Load shared scripts for semantic validation
+        var sharedScriptEntities = await _templateRepo.GetAllSharedScriptsAsync(cancellationToken);
+        var resolvedSharedScripts = sharedScriptEntities.Select(s => new ResolvedScript
+        {
+            CanonicalName = s.Name,
+            Code = s.Code,
+            ParameterDefinitions = s.ParameterDefinitions,
+            ReturnDefinition = s.ReturnDefinition
+        }).ToList();
+
         // Validate
-        var validation = _validationService.Validate(config);
+        var validation = _validationService.Validate(config, resolvedSharedScripts);
 
         // Compute revision hash
         var hash = _revisionHashService.ComputeHash(config);