369 .prm elements exist in the disc's screen builds and every composite is
missing them. Swept statically:
* none of the 369 has a RATC child of its own name — no payload, nothing to
draw, so .prm is a primitive and not a sprite;
* kind & 0x10 and a .prm name agree with ZERO exceptions in either direction
over all 965 builds, so the format marks primitives as a decoded field and a
port need not parse filenames;
* 361 of 369 are exactly 1280x720 at scale 100% in the corner, and their
keyframe 'fade' ARGB is overwhelmingly black at some alpha — these are the
fade-to-black, dim-behind-menu and flash layers, i.e. the PRMD dim-quad the
compositor's backdrop has been standing in for.
Refuted before believing: drawing them at Element::rest() is wrong. The title's
pteff00.prm is opaque -> transparent -> transparent -> opaque, a transition whose
resting pose is the transparent plateau; rest() picks by longest dwell and lands
on the opaque endpoint, which is painted LAST on that screen and would black out
the title. A test asserts that wrong answer deliberately so that fixing the
resting rule fails it and leads to the note.
No compositing change: the resting rule is not .prm-specific and has to be A/B'd
against the title framebuffer capture first.
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