feat(l10n): localize grid-style editor errors by type

Docs/architecture/error-reporting.md

@@ -162,9 +162,46 @@ survives in the log through `CsvService`'s existing `_logger.LogWarning(..., ex.
 coordinator log joiner reads only the top-level `.Message` and does not walk `CausedBy`, so the localized
 headline is what the operator reads while the exception rides the cause for future consumers).
 
-Still free-text (deferred to a later wave): the style-editor and the five formula-internal free-text inners (null expression,
+### The style-editor surface localizes by type
+
+The in-app grid-style editor (`GridStyleEditorViewModel`) localizes its entire `ErrorMessage` surface by
+type. Its two `Result`-join sites (`LoadAsync`, `Save`) route each error through `ReasonLocalizer.Localize`
+rather than joining raw `.Message` strings, so both the validation failures and the file-I/O failures render
+in the current culture. Eight typed producers back it (all in `SemiStep.Core/Configuration/`):
+
+- **Validation** (`GridStyleValidator`): `GridStyleConfigMissingError`, `GridStyleSectionMissingError`,
+  `GridStyleOrientationInvalidError`, `GridStyleKeyMissingError`, `GridStyleHexColorInvalidError`. The
+  orientation error carries its two expected values as properties (`ExpectedRows`/`ExpectedColumns`) rather
+  than referencing the `internal GridOrientationValues` constants, which `ReasonLocalizer` (in `SemiStep.UI`)
+  cannot see.
+- **File I/O** (`GridStyleLoader`/`GridStyleWriter`): `GridStyleConfigNotFoundError` (a leaf), plus the two
+  **Rule-B envelopes** `GridStyleLoadFailedError`/`GridStyleSaveFailedError` (headline only, `.CausedBy(ex)`,
+  the `: {ex.Message}` tail dropped from the sentence).
+
+**Two diagnostics sinks for the Rule-B envelopes.** The loader/writer are logger-less internal helpers, so
+the dropped `ex.Message` is logged at each consumer, and the `ExceptionalError` is nested under `CausedBy`
+(walk one level: `result.Errors.SelectMany(e => e.Reasons).OfType<ExceptionalError>()`):
+
+- **Editor consumer** — `GridStyleEditorViewModel.LoadAsync`/`Save` log each nested `ExceptionalError` at
+  `LogWarning` after setting the localized `ErrorMessage`.
+- **Startup consumer** — `GridStyleLoader`/`GridStyleValidator` are also on the startup config-load path
+  (`ConfigFacade.LoadAndValidateAsync`, consumed by `Program.cs`), which logs the same nested
+  `ExceptionalError` so a YAML parse detail is not lost at launch.
+
+`SaveCommand.ThrownExceptions` (a command-pipeline throw, before any file is written) is distinct: it commits
+to `Resources.SaveFailed` alone (no `grid_style.yaml` in the wording, since no file was touched), with the raw
+exception kept in the log — see the modal-dialog note under "Command-exception pipe".
+
+With this surface typed, the editor no longer shows mixed languages (English loader error next to Russian
+validator error). The **startup** config load — which reads YAML to *establish* the UI culture, so no culture
+exists yet — is now the sole English-by-design surface among the config/recipe/editor operator surfaces
+(the PLC layer keeps two malformed-wire diagnostic edges English by design — the short protocol-version
+read and the codec decode failures — noted in "PLC faults localize by type" below).
+
+Still free-text (deferred to a later wave): the five formula-internal free-text inners (null expression,
 evaluation exception, non-finite, Int32/float overflow), which stay English under `ru` because their inner
-is wrapped in a plain `new Error(text)`. (PLC is now typed — see "PLC faults localize by type" below —
+is wrapped in a plain `new Error(text)`. (The style-editor surface is now typed — see "The style-editor
+surface localizes by type" below. PLC is now typed — see "PLC faults localize by type" below —
 except the short protocol-version read and the codec decode failures, which stay English by design as noted
 there; the enable-catch cancellation message is also plain English, settled by slice 6c.)
 

SemiStep/SemiStep.Core/Configuration/GridStyleConfigMissingError.cs

@@ -0,0 +1,8 @@
+using FluentResults;
+
+namespace SemiStep.Core.Configuration;
+
+public sealed class GridStyleConfigMissingError()
+	: Error("Grid style configuration is missing (ui/grid_style.yaml).")
+{
+}

SemiStep/SemiStep.Core/Configuration/GridStyleConfigNotFoundError.cs

@@ -0,0 +1,9 @@
+using FluentResults;
+
+namespace SemiStep.Core.Configuration;
+
+public sealed class GridStyleConfigNotFoundError(string filePath)
+	: Error($"Grid style config not found: {filePath}")
+{
+	public string FilePath { get; } = filePath;
+}

SemiStep/SemiStep.Core/Configuration/GridStyleHexColorInvalidError.cs

@@ -0,0 +1,13 @@
+using FluentResults;
+
+namespace SemiStep.Core.Configuration;
+
+public sealed class GridStyleHexColorInvalidError(string section, string key, string value)
+	: Error($"Grid style '{section}.{key}' has invalid hex color: '{value}'. Expected format: '#RRGGBB' or '#AARRGGBB'.")
+{
+	public string Section { get; } = section;
+
+	public string Key { get; } = key;
+
+	public string Value { get; } = value;
+}

SemiStep/SemiStep.Core/Configuration/GridStyleKeyMissingError.cs

@@ -0,0 +1,11 @@
+using FluentResults;
+
+namespace SemiStep.Core.Configuration;
+
+public sealed class GridStyleKeyMissingError(string section, string key)
+	: Error($"Grid style '{section}.{key}' is missing or empty.")
+{
+	public string Section { get; } = section;
+
+	public string Key { get; } = key;
+}

SemiStep/SemiStep.Core/Configuration/GridStyleLoadFailedError.cs

@@ -0,0 +1,9 @@
+using FluentResults;
+
+namespace SemiStep.Core.Configuration;
+
+public sealed class GridStyleLoadFailedError(string fileName)
+	: Error($"Failed to load {fileName}")
+{
+	public string FileName { get; } = fileName;
+}

SemiStep/SemiStep.Core/Configuration/GridStyleOrientationInvalidError.cs

@@ -0,0 +1,13 @@
+using FluentResults;
+
+namespace SemiStep.Core.Configuration;
+
+public sealed class GridStyleOrientationInvalidError(string value, string expectedRows, string expectedColumns)
+	: Error($"Grid style 'orientation' has unknown value: '{value}'. Expected '{expectedRows}' or '{expectedColumns}'.")
+{
+	public string Value { get; } = value;
+
+	public string ExpectedRows { get; } = expectedRows;
+
+	public string ExpectedColumns { get; } = expectedColumns;
+}

SemiStep/SemiStep.Core/Configuration/GridStyleSaveFailedError.cs

@@ -0,0 +1,9 @@
+using FluentResults;
+
+namespace SemiStep.Core.Configuration;
+
+public sealed class GridStyleSaveFailedError(string fileName)
+	: Error($"Failed to save {fileName}")
+{
+	public string FileName { get; } = fileName;
+}

SemiStep/SemiStep.Core/Configuration/GridStyleSectionMissingError.cs

@@ -0,0 +1,9 @@
+using FluentResults;
+
+namespace SemiStep.Core.Configuration;
+
+public sealed class GridStyleSectionMissingError(string section)
+	: Error($"Grid style configuration is missing '{section}' section.")
+{
+	public string Section { get; } = section;
+}

SemiStep/SemiStep.Core/Configuration/Loaders/GridStyleLoader.cs

@@ -20,14 +20,14 @@ internal static class GridStyleLoader
 
 		if (!Directory.Exists(uiDir))
 		{
-			return Result.Fail<GridStyleOptionsDto?>($"Grid style config not found: {uiDir}");
+			return Result.Fail<GridStyleOptionsDto?>(new GridStyleConfigNotFoundError(uiDir));
 		}
 
 		var filePath = Path.Combine(uiDir, "grid_style.yaml");
 
 		if (!File.Exists(filePath))
 		{
-			return Result.Fail<GridStyleOptionsDto?>($"Grid style config not found: {filePath}");
+			return Result.Fail<GridStyleOptionsDto?>(new GridStyleConfigNotFoundError(filePath));
 		}
 
 		try
@@ -38,7 +38,7 @@ internal static class GridStyleLoader
 		}
 		catch (Exception ex)
 		{
-			return Result.Fail($"Failed to load {Path.GetFileName(filePath)}: {ex.Message}");
+			return Result.Fail(new GridStyleLoadFailedError(Path.GetFileName(filePath)).CausedBy(ex));
 		}
 	}
 }

SemiStep/SemiStep.Core/Configuration/Loaders/GridStyleWriter.cs

@@ -36,7 +36,7 @@ public Result Save(string configDirectory, GridStyleOptions options)
 		}
 		catch (Exception ex)
 		{
-			return Result.Fail($"Failed to save {Path.GetFileName(filePath)}: {ex.Message}");
+			return Result.Fail(new GridStyleSaveFailedError(Path.GetFileName(filePath)).CausedBy(ex));
 		}
 	}
 

SemiStep/SemiStep.Core/Configuration/Validation/GridStyleValidator.cs

@@ -16,12 +16,12 @@ public static Result Validate(GridStyleOptionsDto? dto)
 	{
 		if (dto is null)
 		{
-			return Result.Fail("Grid style configuration is missing (ui/grid_style.yaml).");
+			return Result.Fail(new GridStyleConfigMissingError());
 		}
 
 		if (dto.Colors is null)
 		{
-			return Result.Fail("Grid style configuration is missing 'colors' section.");
+			return Result.Fail(new GridStyleSectionMissingError("colors"));
 		}
 
 		var errors = new List<IError>();
@@ -182,9 +182,10 @@ private static void ValidateOrientation(string? orientation, List<IError> errors
 			return;
 		}
 
-		errors.Add(new Error(
-			$"Grid style 'orientation' has unknown value: '{orientation}'. " +
-			$"Expected '{GridOrientationValues.RowsAsSteps}' or '{GridOrientationValues.ColumnsAsSteps}'."));
+		errors.Add(new GridStyleOrientationInvalidError(
+			orientation,
+			GridOrientationValues.RowsAsSteps,
+			GridOrientationValues.ColumnsAsSteps));
 	}
 
 	private static void ValidateSection(
@@ -194,7 +195,7 @@ private static void ValidateSection(
 	{
 		if (keys is null)
 		{
-			errors.Add(new Error($"Grid style configuration is missing '{sectionPath}' section."));
+			errors.Add(new GridStyleSectionMissingError(sectionPath));
 			return;
 		}
 
@@ -229,15 +230,13 @@ private static void ValidateKey(string sectionPath, string keyName, string? valu
 	{
 		if (string.IsNullOrWhiteSpace(value))
 		{
-			errors.Add(new Error($"Grid style '{sectionPath}.{keyName}' is missing or empty."));
+			errors.Add(new GridStyleKeyMissingError(sectionPath, keyName));
 			return;
 		}
 
 		if (!_hexColorRegex.IsMatch(value))
 		{
-			errors.Add(new Error(
-				$"Grid style '{sectionPath}.{keyName}' has invalid hex color: '{value}'. " +
-				"Expected format: '#RRGGBB' or '#AARRGGBB'."));
+			errors.Add(new GridStyleHexColorInvalidError(sectionPath, keyName, value));
 		}
 	}
 }

SemiStep/SemiStep.Tests/Core/Configuration/GridStyleEditorFacadeTests.cs

@@ -1,6 +1,9 @@
 using FluentAssertions;
 
+using FluentResults;
+
 using SemiStep.Core.Configuration;
+using SemiStep.Core.Configuration.Loaders;
 using SemiStep.Tests.Config.Helpers;
 using SemiStep.Tests.Helpers;
 
@@ -91,6 +94,42 @@ public async Task Save_InvalidRecord_FailsValidationGuardBeforeWriting()
 		after.Should().Be(before);
 	}
 
+	[Fact]
+	public async Task Load_UnparseableYaml_CarriesOriginalExceptionOnCausedBy()
+	{
+		using var tempDir = new TempDirectory();
+		var uiDir = Path.Combine(tempDir.Path, "ui");
+		Directory.CreateDirectory(uiDir);
+		await File.WriteAllTextAsync(
+			Path.Combine(uiDir, "grid_style.yaml"),
+			": : : not valid yaml @@@ {[",
+			TestContext.Current.CancellationToken);
+
+		var result = await GridStyleLoader.LoadAsync(tempDir.Path);
+
+		result.IsFailed.Should().BeTrue();
+		result.Errors.Should().ContainSingle().Which.Should().BeOfType<GridStyleLoadFailedError>();
+		var exceptional = result.Errors.SelectMany(error => error.Reasons).OfType<ExceptionalError>().ToList();
+		exceptional.Should().ContainSingle();
+		exceptional[0].Exception.Should().NotBeNull();
+	}
+
+	[Fact]
+	public void Save_WriteFailure_CarriesOriginalExceptionOnCausedBy()
+	{
+		using var tempDir = new TempDirectory();
+		var configDirAsFile = Path.Combine(tempDir.Path, "not-a-directory");
+		File.WriteAllText(configDirAsFile, string.Empty);
+
+		var result = new GridStyleWriter().Save(configDirAsFile, GridStyleOptions.Default);
+
+		result.IsFailed.Should().BeTrue();
+		result.Errors.Should().ContainSingle().Which.Should().BeOfType<GridStyleSaveFailedError>();
+		var exceptional = result.Errors.SelectMany(error => error.Reasons).OfType<ExceptionalError>().ToList();
+		exceptional.Should().ContainSingle();
+		exceptional[0].Exception.Should().NotBeNull();
+	}
+
 	private static TempDirectory CopyShippedConfig(string equipment)
 	{
 		var source = ShippedConfigLocator.GetConfigDirectory(equipment);

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

@@ -6,6 +6,7 @@
 
 using FluentResults;
 
+using SemiStep.Core.Configuration;
 using SemiStep.Core.Plc.S7.Protocol;
 using SemiStep.Core.Plc.Sync;
 using SemiStep.Core.Plc.Sync.Ownership;
@@ -37,6 +38,22 @@ public sealed class CoreErrorLocalizationCoverageTests
 			new NotConnectedError(),
 		[typeof(ProtocolVersionMismatchError)] =
 			new ProtocolVersionMismatchError(2, 1),
+		[typeof(GridStyleConfigMissingError)] =
+			new GridStyleConfigMissingError(),
+		[typeof(GridStyleSectionMissingError)] =
+			new GridStyleSectionMissingError("colors"),
+		[typeof(GridStyleOrientationInvalidError)] =
+			new GridStyleOrientationInvalidError("x", "rows_as_steps", "columns_as_steps"),
+		[typeof(GridStyleKeyMissingError)] =
+			new GridStyleKeyMissingError("colors.cells", "depth_0"),
+		[typeof(GridStyleHexColorInvalidError)] =
+			new GridStyleHexColorInvalidError("colors.cells", "depth_0", "zzz"),
+		[typeof(GridStyleConfigNotFoundError)] =
+			new GridStyleConfigNotFoundError("config/ui/grid_style.yaml"),
+		[typeof(GridStyleLoadFailedError)] =
+			new GridStyleLoadFailedError("grid_style.yaml"),
+		[typeof(GridStyleSaveFailedError)] =
+			new GridStyleSaveFailedError("grid_style.yaml"),
 		[typeof(RecipeActiveError)] =
 			new RecipeActiveError(),
 		[typeof(RecipeNotCommittedError)] =