The title screen needs an order that puts element 13 (`ptbase2.t32`, the
full-screen background) behind elements 0-5 (the wordmarks) — the capture shows
the wordmarks on top, so the declaration table is not it. Two other orderings
the bundle carries were the cheap candidates, and both are now dead:
* the **placement region** stores a keyframe group per element with an explicit
element index, so it could be a second ordering. It is not — it equals the
declaration order on every build on the disc. `UiBuild::placement_order`
exposes it and `placement_region_order_is_never_a_second_ordering` pins it, so
the refutation stays checkable instead of remembered.
* the **RATC child order** is the declaration order with the `.prm` elements
absent — strictly less information, and no place to put the background other
than where the table already puts it.
`screen info --geometry` prints both, plus each element's decoded sprite size
beside `pivot*2` and every keyframe's scale/position/time — the numbers a
placement hypothesis has to be tested against, and how the pivot/scale rule in
the previous commit was found.
`title_background_is_full_screen` pins that rule against the disc rather than a
synthetic sprite. `scaled_elements_are_a_small_and_mostly_undiscriminating_minority`
reports the scope honestly: 865 of 5 130 resting placements are scaled at all,
and only 213 of those could tell "about the pivot" from "about the sprite
centre" — which the capture did *not* settle, because `ptbase2`'s pivot is its
centre. It also counts how far `pivot*2` is from the decoded size disc-wide
(2 521 agree, 1 884 are off by more than 16 px), which demotes the "pivot is
exactly half the texture" result to a property of the tutorial bundle.
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