feat: 支持 Python 代码节点 main 返回输出

- 自动传入节点输入并映射 main 返回字典，兼容历史 _result

- 限制脚本输出缓冲并补充运行时与编辑器测试

- 同步 Python 帮助、占位提示和独立可执行补全片段

easyflow-ui-admin/packages/tinyflow-ui/src/components/nodes/CodeNode.svelte

@@ -22,8 +22,8 @@
     let currentNode = useNodesData(currentNodeId);
     const { addParameter } = useAddParameter();
     const { updateNodeData } = useSvelteFlow();
-    const codeNodeHelp = `JavaScript 如何返回结果
-- 定义 main 函数并返回对象，系统会自动执行。
+    const codeNodeHelp = `代码如何返回结果
+- JavaScript 定义 main 函数并返回对象；Python 定义 main 函数并返回 dict，系统会自动执行。
 - main 接收由输入参数组成的对象。
 
 输出参数如何配置
@@ -31,11 +31,15 @@
 - 字段名与 main 返回对象的 key 保持一致。
 - 下游节点可引用：代码节点ID.输出参数名。
 
-示例
-- 代码里写：
+JavaScript 示例
   function main({ input }) {
     return { answer: input, score: 95 };
   }
+
+Python 示例
+  def main(inputs):
+      return {'answer': inputs.get('input'), 'score': 95}
+
 - 输出参数配置：answer(String)、score(Number)
 - 结束节点输出参数可引用：代码节点ID.answer、代码节点ID.score
 
@@ -53,6 +57,13 @@
         const firstAvailable = engines.find((item) => item.selectable !== false);
         return firstAvailable?.value || 'js';
     });
+    const codePlaceholder = $derived.by(() => {
+        const engine = String(data.engine || defaultEngine).trim().toLowerCase();
+        if (engine === 'python' || engine === 'py') {
+            return "请输入代码，例如：def main(inputs):\n    return {'output': inputs.get('input')}";
+        }
+        return '请输入代码，例如：function main({ input }) { return { output: input }; }';
+    });
 
     onMount(async () => {
         const codeEngines = await options.provider?.codeEngine?.();
@@ -118,7 +129,7 @@
         <CodeScriptEditor
                   mode="textarea"
                   rows={10}
-                  placeholder={'请输入代码，例如：function main({ input }) { return { output: input }; }'}
+                  placeholder={codePlaceholder}
                   style="width: 100%"
                   engine={(data.engine as string) || (defaultEngine as string)}
                   parameters={editorParameters}

easyflow-ui-admin/packages/tinyflow-ui/src/components/utils/codeCompletion.test.ts

@@ -71,6 +71,36 @@ describe('codeCompletion utils', () => {
     );
   });
 
+  it('should prefer main return snippets for python output', () => {
+    const completions = createBusinessCompletions('python', []);
+    const mainCompletion = completions.find((item) => item.label === 'main');
+    const resultCompletion = completions.find(
+      (item) => item.label === 'result-object',
+    );
+
+    expect(mainCompletion).toMatchObject({
+      type: 'snippet',
+      detail: '代码节点入口',
+      boost: 1000,
+    });
+    expect(String(mainCompletion?.apply)).toContain('def main(inputs):');
+    expect(String(mainCompletion?.apply)).toContain('return {');
+    expect(String(resultCompletion?.apply)).toContain('def main(inputs):');
+    expect(String(resultCompletion?.apply)).toContain(
+      "return {'message': 'ok', 'data': inputs.get('data')}",
+    );
+  });
+
+  it('should provide standalone python snippets', () => {
+    const completions = createBusinessCompletions('python', []);
+    const snippets = completions.filter((item) => item.type === 'snippet');
+
+    expect(snippets).toHaveLength(4);
+    for (const snippet of snippets) {
+      expect(String(snippet.apply)).toMatch(/^def main\(inputs\):\n    /);
+    }
+  });
+
   it('should detect blocked nodes for comment/string/property contexts', () => {
     expect(shouldSkipBusinessCompletion('Comment')).toBe(true);
     expect(shouldSkipBusinessCompletion('LineComment')).toBe(true);

easyflow-ui-admin/packages/tinyflow-ui/src/components/utils/codeCompletion.ts

@@ -60,21 +60,29 @@ const PYTHON_SNIPPETS: Array<{
   insert: string;
   detail: string;
 }> = [
+  {
+    label: 'main',
+    detail: '代码节点入口',
+    insert:
+      "def main(inputs):\n    return {\n        'output': inputs.get('input'),\n    }",
+  },
   {
     label: 'if-else',
     detail: '条件分支',
     insert:
-      "if condition:\n    _result['value'] = value\nelse:\n    _result['value'] = None",
+      "def main(inputs):\n    condition = inputs.get('condition')\n    value = inputs.get('value')\n    if condition:\n        return {'value': value}\n    return {'value': None}",
   },
   {
     label: 'for-loop',
     detail: '遍历数组',
-    insert: "for item in items:\n    # TODO\n    pass\n_result['done'] = True",
+    insert:
+      "def main(inputs):\n    result = []\n    for item in inputs.get('items', []):\n        result.append(item)\n    return {'result': result}",
   },
   {
     label: 'result-object',
     detail: '返回对象',
-    insert: "_result['message'] = 'ok'\n_result['data'] = data",
+    insert:
+      "def main(inputs):\n    return {'message': 'ok', 'data': inputs.get('data')}",
   },
 ];