`domain/select`: the choosing half of a selection, pure and handed a plain
vector by each site. `pose/held-frame` was already the shared reading half;
nothing chose automatically at all.
The greedy walk rather than the DP, deliberately — it is what the prototype
shipped, and having two implementations is how the DP gets tested. Several tests
pin its exact output for that comparison and will need rewriting when it lands.
Protection is settled before the walk and is not unioned onto its result,
because a protected frame anchors the walk like any other kept frame. The anchor
is what is on screen, so measuring the next frame's drift from a frame that is
no longer displayed holds a one-frame closure across two frames and shows it
twice as long as it was measured. The test that says so is about the picture
rather than the algorithm: the frames the mouth was measured shut on and the
frames the selection shows it shut on are the same list.
A strict local extremum compares against the nearest DIFFERING samples, not the
immediate neighbours, and a run of equal samples is one extremum at the frame it
begins. Immediate neighbours find nothing at all on a closure lasting more than
one frame, which is most of them.
One width for the whole signal, so `distance` is never comparing the prefix two
samples happen to share; a non-finite tolerance falls back to nought, since NaN
compares false against everything and would quietly collapse a performance to a
single pose.
THE EXTREMA HALF HAS NO CALLER under the plan as it now stands, and this is the
commit to revert if it stays that way: `segments`, `turns`, the `:extrema`
branch of `propose` and the multi-component refusal that only guards it, plus
the three tests over them. Plate selections take no extrema by design, and the
performance half gets its closures from the `[:vis]` cut `flow/freeze` already
stores, so nothing asks this code for anything. It is correct and tested and
speculative; docs/frame-selection.md says so beside the build order.
Also corrects `ring/subsample-slots`, which claimed every even budget lands on
the cardinal positions. The corners do; the lip centres survive only multiples
of 4, so the aperture pair cannot be read off a subsampled ring at verts 6, 10,
14 or 18. That is why the performance signal reads a stored cut instead.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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