feat(l10n): localize PLC connection-lost fault

Docs/architecture/error-reporting.md

@@ -42,6 +42,14 @@ How a failed operation reaches the user. Read this before adding a new error-sur
   localizing path; it delegates to the raw `MessagePanelViewModel.ReportWarning(string)` member, which
   stays as the internal sink that accepts an already-composed string. `RowCountMismatchWarning` (the CSV
   row-count mismatch on file load) is the first typed warning to flow through it.
+- `void ReportFailure(this MessagePanelViewModel, IError)` — the single-error twin of
+  `ReportFailure(IResultBase)`/`ReportWarnings`. It localizes **one** transient `IError`
+  (`ReasonLocalizer.Localize(error)`) into the operation slot at `Error` severity, delegating to the raw
+  `ReportError(string)` sink. `IError` is not `IResultBase`, so this is an unambiguous overload, not a new
+  name. It is the localizing path for a fault that arrives as a bare error rather than inside a `Result`:
+  `RecipeCoordinator.OnPlcFault` routes each `IPlcSyncService.Faults` error through it, and
+  `ConnectionLostError` is the first typed PLC fault to flow through it. An untyped inner still falls
+  through to `.Message`, so a free-text `IError` stays English.
 
 A failed operation surfaces **all** of its error messages, not just `Errors[0]`. The message *set* is
 the same one the log records; under `Resources.Culture = ru` the panel text is localized while the log
@@ -63,12 +71,16 @@ template, formatting the structured data into it. An unmapped type falls through
 recurses over `CausedBy` (`IError.Reasons`), so a typed cause nested inside an untyped wrapper still
 localizes.
 
-Localization is applied at exactly **three panel seams**, each of which routes its reasons through
+Localization is applied at exactly **four panel seams**, each of which routes its reasons through
 `ReasonLocalizer.Localize`:
 
-- `ResultReportingExtensions.ReportFailure` — the transient operation channel, error side.
+- `ResultReportingExtensions.ReportFailure(IResultBase)` — the transient operation channel, error side
+  (the localized join of a failed `Result`'s errors).
+- `ResultReportingExtensions.ReportFailure(IError)` — the transient operation channel, single-error side.
+  The single-`IError` twin of the `IResultBase` overload: it localizes one bare transient error (e.g. a
+  PLC fault off `IPlcSyncService.Faults`) rather than a whole `Result`.
 - `ResultReportingExtensions.ReportWarnings` — the transient operation channel, warning side (the twin
-  of `ReportFailure`). Distinct from `RefreshReasons`: `ReportWarnings` carries the outcome of a single
+  of `ReportFailure(IResultBase)`). Distinct from `RefreshReasons`: `ReportWarnings` carries the outcome of a single
   operation, while `RefreshReasons` rebuilds the persistent snapshot-validity list.
 - `MessagePanelViewModel.RefreshReasons` — the persistent validation channel (both the error and the
   warning branch).
@@ -186,9 +198,10 @@ always English; only the panel seams localize.
 - **Persistent structural state** (the current recipe's validity) goes to the validation channel via
   `RefreshReasons`, and from there to the status-bar counts.
 - **PLC connection-loss / sync failures** arrive as a typed `IError` on `IPlcSyncService.Faults`, a
-  discrete one-shot channel. `RecipeCoordinator` bridges each fault to the operation channel via
-  `ReportError(error.Message)` — the message text is owned in Core. The persistent "disconnected"
-  label stays in the status bar.
+  discrete one-shot channel. `RecipeCoordinator.OnPlcFault` bridges each fault to the operation channel
+  via `ReportFailure(error)` (the single-`IError` seam), so a typed fault localizes while the log keeps
+  the English `.Message`. `ConnectionLostError` is the first typed PLC fault; an untyped fault still
+  falls through to its English `.Message`. The persistent "disconnected" label stays in the status bar.
 - **Command exceptions** (a `ReactiveCommand` fault on `ThrownExceptions`) are not `Result`-based;
   they route through `ReportThrownExceptions` (see below) rather than a hand-written handler.
 - **One deliberate exception** to the `"; "` idiom: the clipboard *paste* failure lists each error on

SemiStep/SemiStep.Core/Plc/Sync/ConnectionLostError.cs

@@ -0,0 +1,8 @@
+using FluentResults;
+
+namespace SemiStep.Core.Plc.Sync;
+
+public sealed class ConnectionLostError()
+	: Error("PLC connection lost")
+{
+}

SemiStep/SemiStep.Core/Plc/Sync/PlcSyncCoordinator.cs

@@ -163,7 +163,7 @@ public void ResetForDisable()
 	public void HandleConnectionLost()
 	{
 		_executor.Reset();
-		EmitFault(new Error("PLC connection lost"));
+		EmitFault(new ConnectionLostError());
 	}
 
 	public async Task WaitForPendingSyncAsync(CancellationToken ct = default)

SemiStep/SemiStep.Tests/S7/PlcSyncCoordinatorTests.cs

@@ -238,6 +238,7 @@ public void HandleConnectionLost_EmitsExactlyOneFault()
 
 		faults.Should().ContainSingle(
 			"a runtime connection loss must emit exactly one fault on the Faults channel");
+		faults[0].Should().BeOfType<ConnectionLostError>();
 		faults[0].Message.ToLowerInvariant().Should().Contain("connection");
 	}
 

SemiStep/SemiStep.Tests/UI/Localization/CoreErrorLocalizationCoverageTests.cs

@@ -6,6 +6,7 @@
 
 using FluentResults;
 
+using SemiStep.Core.Plc.Sync;
 using SemiStep.Core.Plc.Sync.Ownership;
 using SemiStep.Core.Recipes;
 using SemiStep.Core.Recipes.Analysis.Warnings;
@@ -29,6 +30,8 @@ public sealed class CoreErrorLocalizationCoverageTests
 {
 	private static readonly IReadOnlyDictionary<Type, IReason> _typeData = new Dictionary<Type, IReason>
 	{
+		[typeof(ConnectionLostError)] =
+			new ConnectionLostError(),
 		[typeof(OwnedByAnotherInstanceError)] =
 			new OwnedByAnotherInstanceError(new OwnerInfo(1, "MACHINE", "alice", DateTimeOffset.UnixEpoch)),
 		[typeof(FormulaComputationFailedError)] =

SemiStep/SemiStep.Tests/UI/Localization/ReasonLocalizerTests.cs

@@ -6,6 +6,7 @@
 
 using FluentResults;
 
+using SemiStep.Core.Plc.Sync;
 using SemiStep.Core.Plc.Sync.Ownership;
 using SemiStep.Core.Recipes;
 using SemiStep.Core.Recipes.Analysis.Warnings;
@@ -60,6 +61,27 @@ public void Localize_OwnedByAnotherInstance_UnderEnglishCulture_MatchesOriginalM
 		}
 	}
 
+	[Fact]
+	public void Localize_ConnectionLost_UnderRussianCulture_RendersRussianSentence()
+	{
+		using (ResourcesCultureScope.Use("ru"))
+		{
+			ReasonLocalizer.Localize(new ConnectionLostError())
+				.Should().Be("Соединение с ПЛК потеряно");
+		}
+	}
+
+	[Fact]
+	public void Localize_ConnectionLost_UnderEnglishCulture_MatchesOriginalMessage()
+	{
+		var error = new ConnectionLostError();
+
+		using (ResourcesCultureScope.Use("en"))
+		{
+			ReasonLocalizer.Localize(error).Should().Be(error.Message);
+		}
+	}
+
 	[Fact]
 	public void Localize_UnmatchedEndForWarning_UnderRussianCulture_RendersRussianSentence()
 	{

SemiStep/SemiStep.Tests/UI/RecipeCoordinatorTests.cs

@@ -8,10 +8,12 @@
 
 using SemiStep.Core.Plc.Configuration;
 using SemiStep.Core.Plc.State;
+using SemiStep.Core.Plc.Sync;
 using SemiStep.Core.Recipes;
 using SemiStep.Tests.Core.Helpers;
 using SemiStep.Tests.Helpers;
 using SemiStep.Tests.UI.Helpers;
+using SemiStep.Tests.UI.Localization;
 
 using SemiStep.UI.Coordinator;
 using SemiStep.UI.Localization;
@@ -374,7 +376,9 @@ public void PlcFault_RoutesToMessagePanelOperationChannel()
 		_fixture.Session.Reset();
 		_fixture.MessagePanel.Entries.Should().BeEmpty("a fresh empty recipe has no structural defects");
 
-		_fixture.PlcSyncService.PushFault(new Error("PLC connection lost"));
+		using var cultureScope = ResourcesCultureScope.Use("en");
+
+		_fixture.PlcSyncService.PushFault(new ConnectionLostError());
 
 		_fixture.MessagePanel.Entries.Should().ContainSingle(
 			"a PLC fault must surface as a transient operation message in the panel");

SemiStep/SemiStep.Tests/UI/ResultReportingExtensionsTests.cs

@@ -6,6 +6,7 @@
 
 using FluentResults;
 
+using SemiStep.Core.Plc.Sync;
 using SemiStep.Core.Recipes.Formulas.Errors;
 
 using SemiStep.Tests.UI.Localization;
@@ -109,4 +110,25 @@ public void ReportFailure_TypedError_UnderRussianCulture_LocalizesInPanel()
 		var entry = _panel.Entries.Should().ContainSingle(item => item.IsError).Subject;
 		entry.Message.Should().Be("Вычисление формулы для цели «temp» не выполнено: min > max");
 	}
+
+	[AvaloniaFact]
+	public void ReportFailure_SingleTypedError_UnderRussianCulture_LocalizesInOperationSlot()
+	{
+		using (ResourcesCultureScope.Use("ru"))
+		{
+			_panel.ReportFailure(new ConnectionLostError());
+		}
+
+		var entry = _panel.Entries.Should().ContainSingle(item => item.IsError).Subject;
+		entry.Message.Should().Be("Соединение с ПЛК потеряно");
+	}
+
+	[AvaloniaFact]
+	public void ReportFailure_SingleUntypedError_FallsThroughToItsMessage()
+	{
+		_panel.ReportFailure((IError)new Error("x"));
+
+		var entry = _panel.Entries.Should().ContainSingle(item => item.IsError).Subject;
+		entry.Message.Should().Be("x");
+	}
 }

SemiStep/SemiStep.UI/Coordinator/RecipeCoordinator.cs

@@ -527,7 +527,7 @@ private void OnPlcFault(IError error)
 			}
 
 			_logger.LogWarning("PLC fault: {Message}", error.Message);
-			_messagePanel.ReportError(error.Message);
+			_messagePanel.ReportFailure(error);
 		}
 	}
 

SemiStep/SemiStep.UI/Localization/ReasonLocalizer.cs

@@ -3,6 +3,7 @@
 
 using FluentResults;
 
+using SemiStep.Core.Plc.Sync;
 using SemiStep.Core.Plc.Sync.Ownership;
 using SemiStep.Core.Recipes.Analysis.Warnings;
 using SemiStep.Core.Recipes.Clipboard.Errors;
@@ -24,6 +25,7 @@ public static string Localize(IReason reason)
 	{
 		var text = reason switch
 		{
+			ConnectionLostError => Resources.ErrorConnectionLost,
 			OwnedByAnotherInstanceError error => Format(
 				Resources.ErrorOwnedByAnotherInstance,
 				error.Holder.UserName,

SemiStep/SemiStep.UI/Localization/Resources.resx

@@ -448,6 +448,9 @@
   <data name="EditorDefaultFont" xml:space="preserve">
     <value>(Default)</value>
   </data>
+  <data name="ErrorConnectionLost" xml:space="preserve">
+    <value>PLC connection lost</value>
+  </data>
   <data name="ErrorOwnedByAnotherInstance" xml:space="preserve">
     <value>PLC sync is owned by another instance (user {0}, since {1:HH:mm} UTC).</value>
   </data>

SemiStep/SemiStep.UI/Localization/Resources.ru.resx

@@ -448,6 +448,9 @@
   <data name="EditorDefaultFont" xml:space="preserve">
     <value>(По умолчанию)</value>
   </data>
+  <data name="ErrorConnectionLost" xml:space="preserve">
+    <value>Соединение с ПЛК потеряно</value>
+  </data>
   <data name="ErrorOwnedByAnotherInstance" xml:space="preserve">
     <value>Синхронизация ПЛК занята другим экземпляром (пользователь {0}, с {1:HH:mm} UTC).</value>
   </data>

SemiStep/SemiStep.UI/MessageService/ResultReportingExtensions.cs

@@ -22,6 +22,11 @@ public static void ReportFailure(this MessagePanelViewModel panel, IResultBase r
 		panel.ReportError(context is null ? message : $"{context}: {message}");
 	}
 
+	public static void ReportFailure(this MessagePanelViewModel panel, IError error)
+	{
+		panel.ReportError(ReasonLocalizer.Localize(error));
+	}
+
 	public static void ReportWarnings(this MessagePanelViewModel panel, IResultBase result)
 	{
 		var message = Join(result.Successes.OfType<Warning>().Select(ReasonLocalizer.Localize));