feat: add MCP support (#1471)

ui/flutter/lib/core/network/gopeed/entry/gopeed_transport_web.dart

@@ -8,7 +8,9 @@ class RestGopeedTransport implements GopeedTransport {
   RestGopeedTransport(GopeedTransportConfig config)
     : _dio = Dio(
         BaseOptions(
-          baseUrl: '${Uri.base.origin}/',
+          // Keep release requests relative so deployments under a reverse
+          // proxy path continue to work, matching the legacy Web client.
+          baseUrl: webTransportBaseUrl(config.address, Uri.base),
           contentType: Headers.jsonContentType,
           sendTimeout: const Duration(seconds: 5),
           connectTimeout: const Duration(seconds: 5),

ui/flutter/lib/core/network/gopeed/gopeed_transport.dart

@@ -1,4 +1,5 @@
 import 'package:dio/dio.dart';
+import 'package:flutter/foundation.dart';
 
 import 'entry/gopeed_transport_stub.dart'
     if (dart.library.html) 'entry/gopeed_transport_web.dart'
@@ -18,6 +19,44 @@ class GopeedTransportConfig {
   final void Function()? onUnauthorized;
 }
 
+const defaultWebApiPort = 9999;
+
+/// Resolves the API base URL used by Flutter Web.
+///
+/// This preserves the legacy behavior: debug builds connect to the local
+/// backend on port 9999, while release builds use the page's server origin.
+String webApiBaseUrl(Uri pageUri, {bool? debugMode}) {
+  final useDebugPort = debugMode ?? kDebugMode;
+  if (useDebugPort) return 'http://127.0.0.1:$defaultWebApiPort/';
+  return '${pageUri.origin}/';
+}
+
+/// Returns the Dio base URL, preserving relative requests in release builds.
+String webTransportBaseUrl(String address, Uri pageUri, {bool? debugMode}) {
+  final useDebugPort = debugMode ?? kDebugMode;
+  return useDebugPort ? normalizeWebApiBaseUrl(address, pageUri) : '';
+}
+
+/// Normalizes either an absolute API URL or a host:port address.
+String normalizeWebApiBaseUrl(String address, Uri pageUri) {
+  var value = address.trim();
+  if (value.isEmpty) return '${pageUri.origin}/';
+
+  final parsed = Uri.tryParse(value);
+  if (parsed != null && parsed.hasScheme && parsed.host.isNotEmpty) {
+    value = Uri(
+      scheme: parsed.scheme,
+      userInfo: parsed.userInfo,
+      host: parsed.host,
+      port: parsed.hasPort ? parsed.port : null,
+      path: parsed.path,
+    ).toString();
+  } else {
+    value = '${pageUri.scheme}://${value.replaceAll(RegExp(r'/+$'), '')}';
+  }
+  return value.endsWith('/') ? value : '$value/';
+}
+
 abstract interface class GopeedTransport {
   Future<dynamic> request(String path, {String method = 'GET', dynamic data, Map<String, dynamic>? queryParameters});