fix(kiosk): restore in-process-gpu + CPUQuota=200% to stop choppy HDMI audio

Both had regressed back to the pre-2026-06-28-incident state: GPU_FLAGS used
--enable-gpu-rasterization on any node with a GPU, and CPUQuota was 75%.
On archy-x250-exp (Intel HD 5500 under X11) this spins a dedicated GPU
process at 55-92% CPU (falls back to software compositing anyway), and the
75% cgroup quota throttled the kiosk unit ~81% of the time (nr_throttled
4856/6005) — the exact CPU-starvation signature documented as the choppy-
audio root cause. Restores the validated fix: --in-process-gpu,
--num-raster-threads=1, GpuRasterization disabled via --disable-features,
CPUQuota=200%. Verified on archy-x250-exp: no separate gpu-process, throttling
dropped to ~3% (nr_throttled 14/503).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

image-recipe/configs/archipelago-kiosk-launcher.sh

@@ -79,12 +79,14 @@ xset s noblank 2>/dev/null || true
 pkill -u archipelago -f 'chromium.*localhost' 2>/dev/null || true
 sleep 1
 
-# GPU vs headless (#36). On a real kiosk display with a GPU, GPU rasterization is
+# GPU vs headless (#36, choppy-audio incident 2026-06-28). --enable-gpu-rasterization
-# fast. On a GPU-less / headless server (no /dev/dri), --enable-gpu-rasterization
+# spins a dedicated GPU process at 55-92% CPU even on real GPU hardware (Intel HD 5500)
-# forces GPU paths that fall back to software compositing and SPIN a full core at
+# because under X11 it falls back to software compositing anyway — that CPU
-# ~92% CPU, saturating the node. Detect the GPU and pick safe flags accordingly.
+# starvation is what caused choppy HDMI audio. --in-process-gpu avoids the
+# separate process; GpuRasterization is also disabled via --disable-features below.
+# On a GPU-less / headless server (no /dev/dri), disable GPU entirely instead.
 if [ -e /dev/dri/card0 ] || [ -e /dev/dri/renderD128 ]; then
-    GPU_FLAGS="--enable-gpu-rasterization --num-raster-threads=2"
+    GPU_FLAGS="--in-process-gpu --num-raster-threads=1"
 else
     GPU_FLAGS="--disable-gpu --num-raster-threads=1"
 fi
@@ -103,7 +105,7 @@ while true; do
       --disable-translate \
       --no-first-run \
       --check-for-update-interval=31536000 \
-      --disable-features=TranslateUI,MetricsReporting,AutofillServerCommunication,PasswordManagerEnabled \
+      --disable-features=TranslateUI,MetricsReporting,AutofillServerCommunication,PasswordManagerEnabled,GpuRasterization \
       --disable-session-crashed-bubble \
       --disable-save-password-bubble \
       --disable-suggestions-service \

image-recipe/configs/archipelago-kiosk.service

@@ -25,8 +25,11 @@ RestartSec=5
 # backend (it caused the .198 receive timeout + deploy storms). Cap CPU + memory
 # so a runaway kiosk can never take the whole machine down; Delegate so the cap
 # also binds the chromium/Xorg children in this unit's cgroup.
+# CPUQuota=75% (0.75 cores) was too tight even for normal playback — the kiosk
+# was throttled ~40% of the time, which is what caused choppy HDMI audio on
+# archy-x250-exp (2026-06-28 incident). 200% (2 cores) gives enough headroom.
 Delegate=yes
-CPUQuota=75%
+CPUQuota=200%
 MemoryMax=1500M
 MemoryHigh=1200M