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/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);