feat: add Python A2A agent example with Nacos registration (#416)

Author: SeasonPilot

python-a2a-agent-example/.env.example

@@ -0,0 +1,40 @@
+#
+# Copyright 2024-2026 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# Python A2A Agent Configuration Example
+# Copy this file to .env and fill in your values
+
+# Agent Configuration
+AGENT_NAME=python-translator-agent
+AGENT_HOST=127.0.0.1
+AGENT_PORT=8000
+
+# Nacos Configuration
+NACOS_SERVER_ADDR=127.0.0.1:8848
+NACOS_NAMESPACE=public
+NACOS_USERNAME=nacos
+NACOS_PASSWORD=nacos
+NACOS_ENABLED=true
+
+# LLM Configuration (DashScope / OpenAI compatible)
+DASHSCOPE_API_KEY=your-dashscope-api-key
+OPENAI_BASE_URL=https://dashscope.aliyuncs.com/compatible-mode/v1
+OPENAI_MODEL=qwen-plus
+
+# Or use standard OpenAI
+# OPENAI_API_KEY=your-openai-api-key
+# OPENAI_BASE_URL=https://api.openai.com/v1
+# OPENAI_MODEL=gpt-4