feat(studio): n8n-endpoints editor in Settings (v0.23.0)

Mirror of the MCP-clients panel: Add / Remove / Refresh
with last-discovery health (workflow count or error_kind),
sister Add-dialog with name + base_url + optional
api_key_env + notes. HubService gains the four passthroughs
(`listN8nEndpoints`, `refreshN8nEndpoints`,
`addN8nEndpoint`, `removeN8nEndpoint`) and a
`N8nEndpointInfo` data class.

Settings dialog now hosts: hub endpoint, channels,
system AI, MCP clients, n8n endpoints — all behind the
existing 520×640 SingleChildScrollView so the layout
doesn't crowd.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/data/hub.dart

@@ -388,6 +388,53 @@ class HubService {
         .toList();
   }
 
+  /// Snapshot of every configured n8n endpoint.
+  Future<List<N8nEndpointInfo>> listN8nEndpoints() async {
+    final r = await _client.listN8nEndpoints();
+    return _mapN8nEndpoints(r);
+  }
+
+  Future<List<N8nEndpointInfo>> refreshN8nEndpoints() async {
+    final r = await _client.refreshN8nEndpoints();
+    return _mapN8nEndpoints(r);
+  }
+
+  Future<List<N8nEndpointInfo>> addN8nEndpoint({
+    required String name,
+    required String baseUrl,
+    String apiKeyEnv = '',
+    String description = '',
+  }) async {
+    final r = await _client.addN8nEndpoint(
+      name: name,
+      baseUrl: baseUrl,
+      apiKeyEnv: apiKeyEnv,
+      description: description,
+    );
+    return _mapN8nEndpoints(r);
+  }
+
+  Future<List<N8nEndpointInfo>> removeN8nEndpoint(String name) async {
+    final r = await _client.removeN8nEndpoint(name);
+    return _mapN8nEndpoints(r);
+  }
+
+  List<N8nEndpointInfo> _mapN8nEndpoints(ListN8nEndpointsResponse r) {
+    return r.endpoints
+        .map(
+          (s) => N8nEndpointInfo(
+            name: s.config.name,
+            baseUrl: s.config.baseUrl,
+            apiKeyEnv: s.config.apiKeyEnv,
+            description: s.config.description,
+            workflowCount: s.workflowCount,
+            errorKind: s.errorKind,
+            message: s.message,
+          ),
+        )
+        .toList();
+  }
+
   /// Active channel + per-channel daemon status snapshot.
   Future<ChannelStatusSnapshot> channelStatus() async {
     final r = await _client.channelStatus();
@@ -975,6 +1022,30 @@ class ChannelStatusSnapshot {
   });
 }
 
+/// One configured n8n endpoint plus the last-discovery
+/// report. Sister of [`McpClientInfo`].
+class N8nEndpointInfo {
+  final String name;
+  final String baseUrl;
+  final String apiKeyEnv;
+  final String description;
+  final int workflowCount;
+  final String errorKind;
+  final String message;
+
+  const N8nEndpointInfo({
+    required this.name,
+    required this.baseUrl,
+    required this.apiKeyEnv,
+    required this.description,
+    required this.workflowCount,
+    required this.errorKind,
+    required this.message,
+  });
+
+  bool get healthy => errorKind.isEmpty && workflowCount > 0;
+}
+
 /// One configured MCP server plus the last-discovery report.
 /// Surfaced by Studio's MCP-clients editor in Settings.
 class McpClientInfo {