Phase 0: drmprobe findings + A1 corrigendum + worklist update

The drm_info-during-playback probe under Wayland confirmed
KWin IS GL-compositing per frame: Plane 39 rotates triple-
buffered ABGR8888 framebuffers (FB IDs 60/61/66) during
playback. The earlier "0% kwin CPU = direct-scanout" reading
in a1_summary.md was a CPU-blind-spot artifact — Panfrost
shader work isn't visible to top or perf-on-userspace.

Corrigendum added to a1_summary.md preserving the original
text as the on-the-day record.

Worklist: A1 entry updated to point at both summaries.

The probe itself was invasive (drm_info every 3s perturbed
KWin's atomic-commit fast-path, kwin %CPU jumped 0->18 median
and 6 drops appeared) — usable diagnostically but cannot be
embedded in measurement reps.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

worklist.md

@@ -102,23 +102,21 @@ inventory and baseline-anchor work below.
 - [x] **A1 baseline: in-session Wayland-with-KWin anchor.**
   Captured 2026-05-03 14:23–14:31 CEST in
   `phase0_evidence/wayland_baseline_2026-05-03/a1_rep[1-3]/`
-  + verdict in `a1_summary.md`. 3 reps,
-  `chromium-fourier-kwin` workload via
-  `run_browser_nodebug.sh`. **Tight cluster (IQR 0):**
-  drops_total=0, drops_post_warmup=0, frames_total=1685
-  (median), kwin %CPU median=0.00, mean=0.04. **Major
-  reframing finding:** kwin_wayland is doing essentially
-  zero per-frame work — perf reports show no GL / dmabuf /
-  composite symbols at all, only event-loop bookkeeping.
-  Most likely mechanism: KWin direct-scanout
-  (single-visible-client bypass). The campaign's
-  load-bearing hypothesis ("X11 will be measurably faster
-  because no KWin GL composite") is structurally weakened
-  — there's no per-frame KWin overhead for the X11 cells
-  to be faster than. Phase 1 needs to add a multi-window
-  A1' variant + drm_info-during-playback to confirm
-  direct-scanout, plus revisit cell-design per
-  `a1_summary.md` § "Phase 1 implications".
+  + original verdict in `a1_summary.md` + **corrected
+  verdict in `drmprobe_findings.md`** (the A1 verdict's
+  "0 % kwin = direct-scanout, hypothesis weakened" claim was
+  wrong — see corrigendum at top of `a1_summary.md`).
+  3 reps tight cluster: drops_total=0, drops_post_warmup=0,
+  frames_total=1685 (median), kwin %CPU median=0.00. The
+  drm_info-during-playback probe revealed Plane 39 rotates
+  triple-buffered ABGR8888 framebuffers — KWin IS GL-
+  compositing per frame, but the work is GPU-side
+  (Panfrost) and invisible to top / perf-on-userspace.
+  **Campaign mechanism is intact.** Phase 1 binding cells
+  need GPU-aware metrics (panfrost devfreq load, frame
+  latency via wp_presentation_feedback / XPresent, power
+  draw) — CPU-only instrumentation will miss the
+  campaign's mechanism every time.
 
 ## Phase 1 — binding cells + measurement protocol