refactor(dotnet): normalize workspace and approval inputs

src/dotnet/QuantEngine.Core.Tests/WorkspaceApprovalServiceTests.cs

@@ -0,0 +1,41 @@
+using Moq;
+using QuantEngine.Application.Services;
+using QuantEngine.Core.Interfaces;
+using QuantEngine.Core.Models;
+
+namespace QuantEngine.Core.Tests;
+
+public class WorkspaceApprovalServiceTests
+{
+    [Fact]
+    public async Task WorkspaceService_RejectsBlankHistoryDomain()
+    {
+        var service = new WorkspaceService(new Mock<IWorkspaceRepository>().Object, new Mock<IPostgresqlHistoryStore>().Object);
+
+        await Assert.ThrowsAsync<ArgumentException>(() =>
+            service.AppendHistoryAsync("  ", new Dictionary<string, object?>()));
+    }
+
+    [Fact]
+    public async Task ApprovalService_NormalizesLookupKeys()
+    {
+        var repo = new Mock<IWorkspaceRepository>(MockBehavior.Strict);
+        repo.Setup(r => r.GetApprovalAsync("workflow", "target-1")).ReturnsAsync(new WorkspaceApproval());
+
+        var service = new ApprovalService(repo.Object);
+
+        var approval = await service.GetApprovalAsync(" workflow ", " target-1 ");
+
+        Assert.NotNull(approval);
+        repo.VerifyAll();
+    }
+
+    [Fact]
+    public async Task ApprovalService_RejectsBlankLockTarget()
+    {
+        var service = new ApprovalService(new Mock<IWorkspaceRepository>().Object);
+
+        await Assert.ThrowsAsync<ArgumentException>(() =>
+            service.ReleaseLockAsync("workflow", " "));
+    }
+}