feat: Implement Authentik group synchronization and add confirmation dialogs for service management

OTSSignsOrchestrator.Core/Services/XiboApiService.cs

@@ -321,6 +321,60 @@ public class XiboApiService
     // User groups
     // ─────────────────────────────────────────────────────────────────────────
 
+    /// <summary>
+    /// Lists all user groups in the Xibo instance and returns their names and IDs.
+    /// </summary>
+    public async Task<List<XiboGroupInfo>> ListUserGroupsAsync(
+        string instanceUrl,
+        string accessToken)
+    {
+        var client  = _httpClientFactory.CreateClient("XiboApi");
+        var baseUrl = instanceUrl.TrimEnd('/');
+
+        SetBearer(client, accessToken);
+
+        var response = await client.GetAsync($"{baseUrl}/api/group");
+        await EnsureSuccessAsync(response, "list Xibo user groups");
+
+        using var doc = await JsonDocument.ParseAsync(await response.Content.ReadAsStreamAsync());
+        var groups = new List<XiboGroupInfo>();
+
+        foreach (var el in doc.RootElement.EnumerateArray())
+        {
+            groups.Add(new XiboGroupInfo
+            {
+                GroupId = el.GetProperty("groupId").GetInt32(),
+                Group   = el.GetProperty("group").GetString() ?? "",
+            });
+        }
+
+        return groups;
+    }
+
+    /// <summary>
+    /// Finds an existing Xibo group by name or creates it if it doesn't exist.
+    /// Returns the group ID.
+    /// </summary>
+    public async Task<int> GetOrCreateUserGroupAsync(
+        string instanceUrl,
+        string accessToken,
+        string groupName)
+    {
+        // Try to find existing group first
+        var existing = await ListUserGroupsAsync(instanceUrl, accessToken);
+        var match = existing.FirstOrDefault(g =>
+            string.Equals(g.Group, groupName, StringComparison.OrdinalIgnoreCase));
+
+        if (match != null)
+        {
+            _logger.LogDebug("Xibo group '{Name}' already exists (id={Id})", groupName, match.GroupId);
+            return match.GroupId;
+        }
+
+        // Create new group
+        return await CreateUserGroupAsync(instanceUrl, accessToken, groupName);
+    }
+
     /// <summary>
     /// Creates a new user group and returns its numeric group ID.
     /// </summary>
@@ -529,6 +583,12 @@ public class XiboTestResult
     public int    HttpStatus { get; set; }
 }
 
+public class XiboGroupInfo
+{
+    public int    GroupId { get; set; }
+    public string Group   { get; set; } = string.Empty;
+}
+
 public class XiboAuthException : Exception
 {
     public int HttpStatus { get; }