fix: drop net48-incompatible TimeoutException filter in timeout catch

The when filter (ex.InnerException is TimeoutException) only matches on
.NET 5+. On .NET Framework 4.8 — which CI exercises via the test project's
net48 target — HttpClient.Timeout throws a bare TaskCanceledException
with no inner exception, so CI failed:

  Expected: typeof(PSProxmoxVE.Core.Exceptions.PveApiException)
  Actual:   typeof(System.Threading.Tasks.TaskCanceledException)
  ---- System.Threading.Tasks.TaskCanceledException : A task was canceled.

PveHttpClient.SendAsync never passes a CancellationToken to the inner
HttpClient.SendAsync, so the only way a TaskCanceledException can reach
this catch is HttpClient.Timeout firing — true on net48, .NET Core, and
.NET 5+. Drop the filter and wrap unconditionally.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/PSProxmoxVE.Core/Client/PveHttpClient.cs

@@ -353,11 +353,12 @@ namespace PSProxmoxVE.Core.Client
             {
                 response = await _httpClient.SendAsync(request).ConfigureAwait(false);
             }
-            catch (TaskCanceledException ex) when (ex.InnerException is TimeoutException)
+            catch (TaskCanceledException ex)
             {
-                // HttpClient.Timeout elapsed. In .NET 5+, HttpClient surfaces transport
-                // timeouts as TaskCanceledException with a TimeoutException inner —
-                // distinguishing them from caller-driven CancellationToken cancellation.
+                // PveHttpClient.SendAsync passes no CancellationToken to HttpClient.SendAsync,
+                // so a TaskCanceledException reaching here can only be HttpClient.Timeout
+                // firing — on .NET Framework, on .NET Core, and on .NET 5+ (where it also
+                // carries a TimeoutException inner). Wrap it uniformly across frameworks.
                 var seconds = _httpClient.Timeout == System.Threading.Timeout.InfiniteTimeSpan
                     ? "infinite"
                     : _httpClient.Timeout.TotalSeconds.ToString("0", System.Globalization.CultureInfo.InvariantCulture) + "s";