re(ui): Q1 -- the interpolation law holds, the group timeline does not

Q1's gate asks whether the ramp is linear. It is, and that result stands:
it rests on the splash's _eff glows, which reproduce exactly. This adds
the part that does not.

The test is a calibration, not a fit. Fix the clock on
palogo_gamearts_eff -- declared 15-unit fade-in 0@15 -> 255@30 against
captured alphas 34,68,102,136,170,204,238, a constant step of 34, giving
t = 2f - 171 -- then check that against the glow's own next landmark: its
declared hold ends t=45, predicted frame 108.0, observed last full-alpha
frame 107. Then apply it to palogo_gamearts in the same bundle and the
same frames, with no free parameter left:

  declared a=232 at t=206 -> frame 188.5, observed alpha 255
  declared a= 32 at t=210 -> frame 190.5, observed alpha 255

The logo is still at full alpha nine frames after it should read 32; its
fade-out runs ~17 frames late; its declared 80-frame fade-in is never
drawn. Not culling -- the same element is submitted down to a=7 on the
way out. Calibration-free version: the declared fade-out spends 12 of 16
units dropping 23/255 of the alpha, and the capture has no such plateau.

Candidate, offered and NOT adopted: if +36 held the NEXT keyframe's time,
the fade-out shape fits (RMS 4.05 vs 12.13, two elements) and the
decoder's "last block's time is unreadable" special case disappears --
the last block would simply have no successor. Rejected for now because
it explains neither the missing fade-in nor the lateness, and because the
_eff elements cannot discriminate between the readings at all (with four
blocks the shift only relabels the phases). Decoder unchanged.

Also withdrawn, mine, within the iteration: "the _eff glows hold a
constant alpha 33". They ramp 34 -> 255 in steps of 34. I printed the
series minimum and read it as its range, with a "14 distinct colours"
column sitting next to it saying otherwise.

docs/re/REFUTED.md

@@ -376,3 +376,12 @@ neighbourhood, not just the line.
 
 * "every IDXD string value is ASCII" → 6 non-ASCII values of 99 328.
 * "`文字列` is a dev placeholder" → they are Shift-JIS **type words**.
+* "the splash `_eff` glows hold a constant α ≈ 33, contradicting their declared
+  255 plateau" → **mine, and refuted within the iteration.** They ramp 34 → 255
+  in exact steps of 34. I had printed the series' minimum and read it as its
+  range. [`ui-keyframe-time-unit.md`](ui-keyframe-time-unit.md)
+* "the declared keyframe timeline reproduces the captured splash" → **refuted for
+  multi-keyframe elements.** `palogo_gamearts` is still at `a=255` nine frames
+  after its declared `a=32`, and its declared 80-frame fade-in is never drawn.
+  The `_eff` glows do reproduce, exactly — so this is about the group timeline,
+  not about the interpolation law. [`ui-keyframe-time-unit.md`](ui-keyframe-time-unit.md)