refactor: 重构聊天模块支持 SSE 断线重连及用户上下文隔离

apps/lib/features/chat/data/apis/chat_api_impl.dart

@@ -25,16 +25,16 @@ class ChatApiImpl implements ChatApi {
   @override
   Future<Stream<String>> streamRunEvents(
     String threadId, {
+    required String runId,
     String? lastEventId,
   }) {
     final headers = <String, String>{'Accept': 'text/event-stream'};
     if (lastEventId != null && lastEventId.isNotEmpty) {
       headers['Last-Event-ID'] = lastEventId;
     }
-    return _apiClient.getSseLines(
-      '/api/v1/agent/runs/$threadId/events',
-      headers: headers,
-    );
+    final encodedRunId = Uri.encodeQueryComponent(runId);
+    final path = '/api/v1/agent/runs/$threadId/events?runId=$encodedRunId';
+    return _apiClient.getSseLines(path, headers: headers);
   }
 
   @override