[release tool]: merge staging pull requests through the tool itself

Currently it is unclear what should be used to merge staging pull requests. We should just let the release tool merge the PR as it knows exactly where the PR should go into. The merge tool would rely on target labels which might not work temporarily e.g. when branching-off a feature freeze.

We should either merge automatically once the PR is approved + checks are passing, or we just add a double-prompt that can be submitted to manually start the merging (useful in case the PR checks are not significant as in COMP and FW - though worth noting that this could be done through a configuration as well in `.ng-dev`.)

The cherry-pick PRs should be merged automatically based on our discussion

首先定位 release 工具的 staging pull request 合并流程，并检查 issue 中提到的 `.ng-dev` 配置。将自动合并与提议的双重提示和配置选项进行比较，包括所述的 cherry-pick 行为。对于所述的 staging 和 cherry-pick 情况，合并策略完成决策并实现后，即视为完成。

由索引模型根据 Issue 内容生成。