feat(m1): storage layer

- Shared SQLite plumbing: PRAGMAs (WAL/NORMAL/foreign_keys) and
  user_version migrations with typed SchemaVersionException
- Workspace folder: .ykanban initialization, empty schema with
  DDL-level constraints, preset column seeding (ResX-driven),
  exclusive lock file with holder diagnostics
- AppData folder: app.db workspace registry (injectable clock),
  app.json config store with kebab-case JSON names via explicit
  [JsonProperty]/[EnumMember], nested sections, corrupt-file backup
- ResX infrastructure under Assets/Locales (en + zh-Hans) with
  MSBuild strongly-typed public Resources class
- 54 unit tests: DDL constraints, migrations, PRAGMAs, lock
  exclusivity, config degradation, culture-aware presets

YKanBan.Tests/Storage/Workspace/PresetColumnCultureTests.cs

@@ -0,0 +1,59 @@
+using System.Globalization;
+using YKanBan.Storage.Workspace;
+using YKanBan.Tests.TestUtilities;
+
+namespace YKanBan.Tests.Storage.Workspace;
+
+/// <summary>
+/// Verifies that preset column titles follow the UI language active at
+/// seeding time and then live as ordinary data. Mutates the global
+/// Resources.Culture, therefore marked DoNotParallelize.
+/// </summary>
+[TestClass]
+[DoNotParallelize]
+public class PresetColumnCultureTests
+{
+    [TestMethod]
+    public void PresetTitlesAreEnglishUnderEnglishCulture()
+    {
+        CultureInfo? original = Resources.Culture;
+        try
+        {
+            Resources.Culture = new CultureInfo("en");
+            using var directory = new TempDirectory();
+            WorkspaceInitializer.Initialize(directory.FullPath);
+            WorkspacePreset.SeedColumns(directory.FullPath);
+
+            using var connection = SqliteTestHelper.OpenWorkspace(directory.FullPath);
+            CollectionAssert.AreEqual(
+                new[] { "To Do", "In Progress", "Done" },
+                SqliteTestHelper.GetColumnTitles(connection));
+        }
+        finally
+        {
+            Resources.Culture = original;
+        }
+    }
+
+    [TestMethod]
+    public void PresetTitlesAreChineseUnderChineseCulture()
+    {
+        CultureInfo? original = Resources.Culture;
+        try
+        {
+            Resources.Culture = new CultureInfo("zh-Hans");
+            using var directory = new TempDirectory();
+            WorkspaceInitializer.Initialize(directory.FullPath);
+            WorkspacePreset.SeedColumns(directory.FullPath);
+
+            using var connection = SqliteTestHelper.OpenWorkspace(directory.FullPath);
+            CollectionAssert.AreEqual(
+                new[] { "待办", "进行中", "已完成" },
+                SqliteTestHelper.GetColumnTitles(connection));
+        }
+        finally
+        {
+            Resources.Culture = original;
+        }
+    }
+}