feat: ed2k protocol support (#1316)

ui/flutter/lib/api/model/downloader_config.dart

@@ -31,6 +31,7 @@ class DownloaderConfig {
 class ProtocolConfig {
   HttpConfig http = HttpConfig();
   BtConfig bt = BtConfig();
+  Ed2kConfig ed2k = Ed2kConfig();
 
   ProtocolConfig();
 
@@ -80,6 +81,28 @@ class BtConfig {
   Map<String, dynamic> toJson() => _$BtConfigToJson(this);
 }
 
+@JsonSerializable()
+class Ed2kConfig {
+  int listenPort;
+  int udpPort;
+  String serverAddr;
+  String serverMet;
+  String nodesDat;
+
+  Ed2kConfig({
+    this.listenPort = 0,
+    this.udpPort = 0,
+    this.serverAddr = '',
+    this.serverMet = '',
+    this.nodesDat = '',
+  });
+
+  factory Ed2kConfig.fromJson(Map<String, dynamic> json) =>
+      _$Ed2kConfigFromJson(json);
+
+  Map<String, dynamic> toJson() => _$Ed2kConfigToJson(this);
+}
+
 @JsonSerializable(explicitToJson: true)
 class ExtraConfig {
   String themeMode;

ui/flutter/lib/api/model/downloader_config.g.dart

@@ -42,12 +42,15 @@ Map<String, dynamic> _$DownloaderConfigToJson(DownloaderConfig instance) =>
 ProtocolConfig _$ProtocolConfigFromJson(Map<String, dynamic> json) =>
     ProtocolConfig()
       ..http = HttpConfig.fromJson(json['http'] as Map<String, dynamic>)
-      ..bt = BtConfig.fromJson(json['bt'] as Map<String, dynamic>);
+      ..bt = BtConfig.fromJson(json['bt'] as Map<String, dynamic>)
+      ..ed2k = Ed2kConfig.fromJson(
+          json['ed2k'] as Map<String, dynamic>? ?? <String, dynamic>{});
 
 Map<String, dynamic> _$ProtocolConfigToJson(ProtocolConfig instance) =>
     <String, dynamic>{
       'http': instance.http.toJson(),
       'bt': instance.bt.toJson(),
+      'ed2k': instance.ed2k.toJson(),
     };
 
 HttpConfig _$HttpConfigFromJson(Map<String, dynamic> json) => HttpConfig(
@@ -82,6 +85,23 @@ Map<String, dynamic> _$BtConfigToJson(BtConfig instance) => <String, dynamic>{
       'seedTime': instance.seedTime,
     };
 
+Ed2kConfig _$Ed2kConfigFromJson(Map<String, dynamic> json) => Ed2kConfig(
+      listenPort: (json['listenPort'] as num?)?.toInt() ?? 0,
+      udpPort: (json['udpPort'] as num?)?.toInt() ?? 0,
+      serverAddr: json['serverAddr'] as String? ?? '',
+      serverMet: json['serverMet'] as String? ?? '',
+      nodesDat: json['nodesDat'] as String? ?? '',
+    );
+
+Map<String, dynamic> _$Ed2kConfigToJson(Ed2kConfig instance) =>
+    <String, dynamic>{
+      'listenPort': instance.listenPort,
+      'udpPort': instance.udpPort,
+      'serverAddr': instance.serverAddr,
+      'serverMet': instance.serverMet,
+      'nodesDat': instance.nodesDat,
+    };
+
 ExtraConfig _$ExtraConfigFromJson(Map<String, dynamic> json) => ExtraConfig(
       themeMode: json['themeMode'] as String? ?? '',
       locale: json['locale'] as String? ?? '',

ui/flutter/lib/api/model/task.dart

@@ -6,7 +6,7 @@ part 'task.g.dart';
 
 enum Status { ready, running, pause, wait, error, done }
 
-enum Protocol { http, bt }
+enum Protocol { http, bt, ed2k }
 
 // ExtractStatus enum matching Go backend
 enum ExtractStatus {

ui/flutter/lib/api/model/task.g.dart

@@ -51,6 +51,7 @@ const _$StatusEnumMap = {
 const _$ProtocolEnumMap = {
   Protocol.http: 'http',
   Protocol.bt: 'bt',
+  Protocol.ed2k: 'ed2k',
 };
 
 Progress _$ProgressFromJson(Map<String, dynamic> json) => Progress(