re: build the fast probe -- and it refutes the diagnosis that motivated it

Last iteration I blamed four failed runs on the probe sampling every
~41 s, slower than the title screen lasts, and withdrew three earlier
conclusions on that basis. Building the fix tested the claim and killed
it.

The speedup is real and control-verified. One long-lived ffmpeg x11grab
stream, raw RGB, glyph counted in numpy -- no per-sample process startup,
no PNG encode, no convert -crop:

  wrapper `screenshot`            3.98 s per sample (emulator running)
  import -window root -> PPM      1.20 s
  long-lived x11grab stream       0.29 s          13.7x

The counter is byte-identical to is_title.py: 753 on the committed title
capture, 327 on the main menu.

Pointed at a running game it says the opposite of what I expected:

  332 frames in  85.3 s = 3.89 fps; max glyph 0
  1674 frames in 420.0 s = 3.99 fps; max glyph 0

1674 consecutive samples over seven unbroken minutes, four per second,
zero green-(A) pixels. Sampling rate was a real defect that happened not
to be the cause.

So "neither locale reaches the interactive title without a pad press" --
withdrawn last iteration for want of evidence -- is reinstated, now as a
dense measurement, with its reach stated: a MID-RUN window only, silent
about the boot title.

Leading hypothesis, unconfirmed: the PRESS (A) plate appears only in the
boot title window and the attract loop's title carries none, which is
exactly what title_states_capture.sh was written to test. The experiment
is to start the fast probe from t=0 rather than attach to a run already
in progress.

METHOD: fixing the instrument is how you test the explanation that blamed
it -- a plausible mechanism is a hypothesis, and the fix is its
experiment, not its proof.

docs/re/REFUTED.md

@@ -436,3 +436,13 @@ neighbourhood, not just the line.
   costs 10.8 s while the emulator runs (0.117 s idle, 92×). A title lasting a few
   seconds would be missed. The observations stand; the conclusions drawn from
   them do not. [`capture-harness-status.md`](capture-harness-status.md)
+* "the boot harness fails because its polling loop samples every ~41 s, slower
+  than the title screen lasts" → **mine, and refuted by my own fix.** The
+  sampling defect was real (3.98 s → 0.29 s per sample, 13.7×, control-verified
+  at 753/327), but a probe running at 3.99 fps for **420 continuous seconds —
+  1 674 samples — still saw zero green-Ⓐ pixels.** Sampling rate was not the
+  cause. [`capture-harness-status.md`](capture-harness-status.md)
+* ~~"neither locale reaches the interactive title without a pad press"~~ →
+  withdrawn last iteration for want of evidence, now **reinstated as a
+  measurement**: 1 674 dense samples over 420 s, English, zero glyph frames.
+  ⚠️ Reach: a mid-run window only; it says nothing about the boot title.