Covers the facets' counts and their appear-only-when-real rules, the bucket/slider mirroring (contiguous unions read as a range, gap-skipping selections dim it), sort semantics (natural direction per key, meaning-labelled asc/desc, active key a no-op), Clear resetting filters while keeping sort, the group-by toggle, and the "/" search shortcut with its keycap chip.

## Before writing SPEC.md files

Read https://raw.githubusercontent.com/brillout/sdd/refs/heads/main/sdd.md
