test(config): accept IOException from the atomic config-write path

The atomic-write seam (AtomicFile, introduced earlier in this change) replaces a
File.WriteAllText with a temp-write + File.Move. Writing to a path that is a
directory therefore now throws IOException ('Is a directory') from File.Move
rather than the UnauthorizedAccessException that File.WriteAllText raised, so
SubmitCurrentConfigurationAsync_surfaces_persistence_exception_to_awaited_caller
asserted the wrong exact type.

The test's contract is that the awaited path surfaces (does not swallow) a
persistence failure. Assert that a persistence IO exception propagates — either
IOException or UnauthorizedAccessException, robust across OS/write mechanism — while
still rejecting an unexpected exception type. Production write surfaces already
catch both types, so there is no runtime gap.

Author: Aaronontheweb

src/Netclaw.Cli.Tests/Tui/Config/SearchConfigEditorViewModelTests.cs

@@ -150,8 +150,15 @@ public async Task SubmitCurrentConfigurationAsync_surfaces_persistence_exception
         using var vm = CreateBraveEditorWithSuccessfulProbe();
         ReplaceConfigFileWithDirectory();
 
-        await Assert.ThrowsAsync<UnauthorizedAccessException>(
+        // The awaited path surfaces the persistence failure to the caller (unlike the from-input path,
+        // which catches it into a status). The exact type depends on the OS/write mechanism — the
+        // atomic write's File.Move onto a directory throws IOException, a denied open throws
+        // UnauthorizedAccessException — so accept either persistence-IO exception rather than pinning
+        // one, while still rejecting an unexpected exception.
+        var ex = await Assert.ThrowsAnyAsync<SystemException>(
             () => vm.SubmitCurrentConfigurationAsync(TestContext.Current.CancellationToken));
+        Assert.True(ex is IOException or UnauthorizedAccessException,
+            $"Expected a persistence IO exception, got {ex.GetType().Name}: {ex.Message}");
     }
 
     [Fact]