feat: add JoeAppEngine OPC UA nodes, fix DCL auto-reconnect and quality push

- Add JoeAppEngine folder to OPC UA nodes.json (BTCS, AlarmCntsBySeverity, Scheduler/ScanTime)
- Fix DataConnectionActor: capture Self in PreStart for use from non-actor threads,
  preventing Self.Tell failure in Disconnected event handler
- Implement InstanceActor.HandleConnectionQualityChanged to mark attributes Bad on disconnect
- Fix LmxFakeProxy TagMapper to serialize arrays as JSON instead of "System.Int32[]"
- Allow DataType and DataSourceReference updates in TemplateService.UpdateAttributeAsync
- Update test_infra_opcua.md with JoeAppEngine documentation

src/ScadaLink.Commons/Interfaces/Protocol/IDataConnection.cs

@@ -22,4 +22,11 @@ public interface IDataConnection : IAsyncDisposable
     Task<IReadOnlyDictionary<string, WriteResult>> WriteBatchAsync(IDictionary<string, object?> values, CancellationToken cancellationToken = default);
     Task<bool> WriteBatchAndWaitAsync(IDictionary<string, object?> values, string flagPath, object? flagValue, string responsePath, object? responseValue, TimeSpan timeout, CancellationToken cancellationToken = default);
     ConnectionHealth Status { get; }
+
+    /// <summary>
+    /// Raised when the adapter detects an unexpected connection loss (e.g., gRPC stream error,
+    /// network timeout). The DataConnectionActor listens for this to trigger reconnection
+    /// and push bad quality to all subscribed tags.
+    /// </summary>
+    event Action? Disconnected;
 }

src/ScadaLink.Commons/Messages/Health/SiteHealthReport.cs

@@ -14,4 +14,5 @@ public record SiteHealthReport(
     int DeadLetterCount,
     int DeployedInstanceCount,
     int EnabledInstanceCount,
-    int DisabledInstanceCount);
+    int DisabledInstanceCount,
+    string NodeRole = "Unknown");

src/ScadaLink.Commons/Messages/Management/DeploymentCommands.cs

@@ -2,3 +2,4 @@ namespace ScadaLink.Commons.Messages.Management;
 
 public record MgmtDeployArtifactsCommand(int? SiteId = null);
 public record QueryDeploymentsCommand(int? InstanceId = null, string? Status = null, int Page = 1, int PageSize = 50);
+public record GetDeploymentDiffCommand(int InstanceId);

src/ScadaLink.Commons/Messages/Management/InstanceCommands.cs

@@ -8,3 +8,5 @@ public record MgmtEnableInstanceCommand(int InstanceId);
 public record MgmtDisableInstanceCommand(int InstanceId);
 public record MgmtDeleteInstanceCommand(int InstanceId);
 public record SetConnectionBindingsCommand(int InstanceId, IReadOnlyList<(string AttributeName, int DataConnectionId)> Bindings);
+public record SetInstanceOverridesCommand(int InstanceId, IReadOnlyDictionary<string, string?> Overrides);
+public record SetInstanceAreaCommand(int InstanceId, int? AreaId);

src/ScadaLink.Commons/Messages/Management/RemoteQueryCommands.cs

@@ -1,4 +1,6 @@
 namespace ScadaLink.Commons.Messages.Management;
 
-public record QueryEventLogsCommand(string SiteIdentifier, string? EventType = null, string? Severity = null, string? Keyword = null, DateTimeOffset? From = null, DateTimeOffset? To = null, int Page = 1, int PageSize = 50);
+public record QueryEventLogsCommand(string SiteIdentifier, string? EventType = null, string? Severity = null, string? Keyword = null, DateTimeOffset? From = null, DateTimeOffset? To = null, int Page = 1, int PageSize = 50, string? InstanceName = null);
 public record QueryParkedMessagesCommand(string SiteIdentifier, int Page = 1, int PageSize = 50);
+public record RetryParkedMessageCommand(string SiteIdentifier, string MessageId);
+public record DiscardParkedMessageCommand(string SiteIdentifier, string MessageId);

src/ScadaLink.Commons/Messages/Management/SecurityCommands.cs

@@ -11,3 +11,4 @@ public record UpdateApiKeyCommand(int ApiKeyId, bool IsEnabled);
 public record ListScopeRulesCommand(int MappingId);
 public record AddScopeRuleCommand(int MappingId, int SiteId);
 public record DeleteScopeRuleCommand(int ScopeRuleId);
+public record ResolveRolesCommand(IReadOnlyList<string> LdapGroups);

src/ScadaLink.Commons/Messages/RemoteQuery/ParkedMessageDiscardRequest.cs

@@ -0,0 +1,18 @@
+namespace ScadaLink.Commons.Messages.RemoteQuery;
+
+/// <summary>
+/// Request to permanently discard a parked message at a site.
+/// </summary>
+public record ParkedMessageDiscardRequest(
+    string CorrelationId,
+    string SiteId,
+    string MessageId,
+    DateTimeOffset Timestamp);
+
+/// <summary>
+/// Response from discarding a parked message.
+/// </summary>
+public record ParkedMessageDiscardResponse(
+    string CorrelationId,
+    bool Success,
+    string? ErrorMessage = null);

src/ScadaLink.Commons/Messages/RemoteQuery/ParkedMessageRetryRequest.cs

@@ -0,0 +1,18 @@
+namespace ScadaLink.Commons.Messages.RemoteQuery;
+
+/// <summary>
+/// Request to retry a parked message at a site (move back to pending queue).
+/// </summary>
+public record ParkedMessageRetryRequest(
+    string CorrelationId,
+    string SiteId,
+    string MessageId,
+    DateTimeOffset Timestamp);
+
+/// <summary>
+/// Response from retrying a parked message.
+/// </summary>
+public record ParkedMessageRetryResponse(
+    string CorrelationId,
+    bool Success,
+    string? ErrorMessage = null);