Enhance SwarmUI integration by adding swarm connection status to the API and updating client-side components to reflect this status. Improved localization strings for various SwarmUI states and refactored ApplicantsDialog and PersonCard components to utilize the new connection information, ensuring a more responsive user experience.

src/HSchool.Server/Game/SwarmUiClient.cs

@@ -28,6 +28,33 @@ internal sealed class SwarmUiClient
 
     public bool IsConfigured => !string.IsNullOrWhiteSpace(_options.BaseUrl);
 
+    /// <summary>Opens a session to verify SwarmUI responds; does not generate an image.</summary>
+    public async Task<bool> ProbeAsync(TimeSpan timeout, CancellationToken cancellationToken)
+    {
+        if (!IsConfigured)
+        {
+            return false;
+        }
+
+        using var timeoutSource = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
+        timeoutSource.CancelAfter(timeout);
+
+        try
+        {
+            await RefreshSessionAsync(timeoutSource.Token);
+            return true;
+        }
+        catch (OperationCanceledException) when (!cancellationToken.IsCancellationRequested)
+        {
+            return false;
+        }
+        catch (Exception ex)
+        {
+            _logger.LogDebug(ex, "SwarmUI probe failed.");
+            return false;
+        }
+    }
+
     public async Task<byte[]> GenerateAsync(
         string prompt,
         string negativePrompt,

src/HSchool.Server/Game/SwarmUiHealthService.cs

@@ -0,0 +1,43 @@
+namespace HSchool.Server.Game;
+
+/// <summary>Caches a lightweight SwarmUI reachability probe so /api/status stays cheap.</summary>
+internal sealed class SwarmUiHealthService(SwarmUiClient client)
+{
+    private static readonly TimeSpan CacheTtl = TimeSpan.FromSeconds(15);
+    private static readonly TimeSpan ProbeTimeout = TimeSpan.FromSeconds(5);
+
+    private readonly SemaphoreSlim _gate = new(1, 1);
+    private bool? _lastConnected;
+    private DateTime _lastCheckUtc = DateTime.MinValue;
+
+    /// <summary><c>null</c> when SwarmUI is not configured.</summary>
+    public async Task<bool?> GetConnectedAsync(CancellationToken cancellationToken)
+    {
+        if (!client.IsConfigured)
+        {
+            return null;
+        }
+
+        if (DateTime.UtcNow - _lastCheckUtc < CacheTtl && _lastConnected.HasValue)
+        {
+            return _lastConnected;
+        }
+
+        await _gate.WaitAsync(cancellationToken);
+        try
+        {
+            if (DateTime.UtcNow - _lastCheckUtc < CacheTtl && _lastConnected.HasValue)
+            {
+                return _lastConnected;
+            }
+
+            _lastConnected = await client.ProbeAsync(ProbeTimeout, cancellationToken);
+            _lastCheckUtc = DateTime.UtcNow;
+            return _lastConnected;
+        }
+        finally
+        {
+            _gate.Release();
+        }
+    }
+}