Star-tree Optimizations

Problems:
1. Certain predicates (e.g. `NOT_EQUAL`) can select too many branches, limiting the performance of star-tree
2. Star-tree does not support filters with `OR`

Potential solutions for 1:
- During aggregation, negate the aggregation result of the non-selected branches from the star node branch. This solution could become complicated for multiple predicates.
- Create a derived column for the predicate result, and apply star-tree on top of it. This solution can only work on the fixed predicate.
- First use inverted index to do the filtering, then use pre-aggregated docs to cover the contiguous selected docs

Potential solution for 2:
- Use bitmap to store the selected docs for each predicate under `OR`, then union the bitmaps

No files, tests, or entry points are named. Start by locating the star-tree predicate and aggregation handling, then compare the two listed problem areas and their potential solutions; the issue does not define an acceptance criterion for when either optimization is complete.

Written by the indexing model from the issue text.