Change Group Membership as the Result of an Evaluation

Basically, we should check if someone is in the Intro Members group and if they fail Spring Evals they should be removed from both that group and the Active group when they fail.

Stretch goal: We should also remove people from Intro Members if they pass a Spring Eval.

在 Python/Flask 应用中搜索 Spring Eval 结果处理以及对 Intro Members 和 Active 组的更新。先追踪现有的成员变更路径，然后验证失败的评估会将该人员从两个组中移除；延伸目标包括通过评估后将其从 Intro Members 中移除。如果项目已有既定的测试路径，请定位或添加针对这些结果的专门测试。

由索引模型根据 Issue 内容生成。