Specifies the ctrl-k command bar for both clients: opening and the
leader escape hatch for a literal Ctrl-K, sigils, empty-query recency,
the key model including the session action page, and touch entry.
The match-and-rank algorithm is pinned exactly — normalization, word
boundaries, the per-character score, embedding choice, tie-break — and
closed with twelve fixtures the TypeScript (#146) and Rust (#147)
matchers are both tested against, so their orders cannot drift.
