Nested groups (groups within groups)

Problem
Users organize checks by feature using groups, but for large-scale accounts a single feature can contain hundreds of tests. Even after grouping by feature, the group itself becomes too large to navigate. There's currently no way to further subdivide a group into logical sub-groups while keeping them under one parent.

Ask
Support hierarchical groups: a group can contain other groups in addition to checks. Users should be able to nest groups multiple levels deep, move existing groups under a new parent, and view rollup status (pass/fail, availability, response time percentiles) at any level of the hierarchy.

Example structures users want

• Payment (parent) > Credit card, ACH, Wallet (children)

• Authentication (parent) > Email auth, SSO, Social login (children)

• Account limits (parent) > v1, v2 (children)