Review 1.3: a request that fails in an unexpected way is completed as failed, not left Running

HandleAsync only turned a few exception types into the request's error; anything
else (a lock or command timeout, a JSON or argument error) escaped, leaving the
row Running and the page waiting until housekeeping failed it minutes later.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/SQLInsight.Agent/Configuration/AgentRequestService.cs

@@ -104,7 +104,9 @@ public sealed partial class AgentRequestService(
         {
             error = $"Agenten fik ikke svar inden for {RequestTimeout.TotalMinutes:0} minutter.";
         }
-        catch (Exception ex) when (ex is CredentialException or KeyNotFoundException or InvalidOperationException or DiscoveryFailedException or DbException)
+        // Anything else (a lock timeout, a repository error while storing a discovery …) is the request's result too, so it
+        // is never left as Running for the web UI to wait on.
+        catch (Exception ex) when (ex is not OperationCanceledException)
         {
             error = ex.Message;
         }