feat: add storage foundation and i18n resources

YKanBan.Tests/TestUtilities/TempDirectory.cs

@@ -0,0 +1,43 @@
+namespace YKanBan.Tests.TestUtilities;
+
+/// <summary>
+/// Creates a unique temporary directory per test instance and removes it on
+/// disposal. The removal is retried once because SQLite WAL sidecar files can
+/// linger for a moment after the connections close.
+/// </summary>
+public sealed class TempDirectory : IDisposable
+{
+    /// <summary>
+    /// Gets the unique directory path managed by this instance.
+    /// </summary>
+    public string FullPath { get; }
+
+    public TempDirectory()
+    {
+        FullPath = Path.Combine(Path.GetTempPath(), "ykanban-tests-" + Guid.NewGuid().ToString("N"));
+        Directory.CreateDirectory(FullPath);
+    }
+
+    /// <summary>
+    /// Deletes the directory tree, retrying once after a short delay.
+    /// </summary>
+    public void Dispose()
+    {
+        try
+        {
+            Directory.Delete(FullPath, recursive: true);
+        }
+        catch (IOException)
+        {
+            Thread.Sleep(100);
+            try
+            {
+                Directory.Delete(FullPath, recursive: true);
+            }
+            catch (IOException)
+            {
+                // Leftovers in the OS temp folder are harmless; never fail a test over cleanup.
+            }
+        }
+    }
+}