Address two Greptile review comments:
1. Collapsed parent badge now shows total descendant count at all depths
rather than direct-child count only. Add `countDescendants` utility to
issue-tree.ts (recursive, uses existing childMap) and replace
`children.length` with it in the titleSuffix badge.
2. Add a useEffect that prunes stale IDs from `collapsedParents` whenever
the issues prop changes. Deleted or reassigned issues previously left
orphan IDs in localStorage indefinitely; the effect filters to only IDs
that appear as a parentId in the current issue list and persists the
cleaned array via updateView.
Add four unit tests for countDescendants: leaf node, single-level,
multi-level, and unknown ID.
Co-Authored-By: Paperclip <noreply@paperclip.ing>
Darren Davison
7623f679cf