fix(promote): 补充 validate job 的 outputs 声明以启用跨 job 输出传递;

GitHub Actions 中 core.setOutput() 仅创建步骤级输出，跨 job 访问
必须在 job 级别显式声明 outputs 映射。原 validate job 缺少此声明，
导致 needs.validate.outputs.* 在 promote job 中全部为空。

🤖 Generated with [Claude Code](https://github.com/claude), [CodeX](https://openai.com), [Gemini](https://github.com/apps/gemini-code-assist)
Co-Authored-By: Aurelius Huang<threefish.ai@gmail.com>

Author: ThreeFish-AI

.github/workflows/promote.yml

@@ -54,6 +54,9 @@ jobs:
     name: Validate prerelease status
     runs-on: ubuntu-latest
     timeout-minutes: 5
+    outputs:
+      release_id: ${{ steps.check-release.outputs.release_id }}
+      tag_name: ${{ steps.check-release.outputs.tag_name }}
 
     steps:
       - name: Check release exists and is a prerelease