feat(theme-studio): screenshot harness + ecosystem coverage policy

Two speedrun-enabling pieces. A #preview=<app>&theme=<json> hash handler plus screenshot-previews.sh shoot any app's face table and live preview headlessly under a real theme (WIP.json by default), so preview work can be verified without a human clicking through the studio. The README gains the coverage policy: the studio themes popular packages even when uninstalled, pinning their faces rather than dropping them, and unloaded packages' previews matter more, not less.

1 files changed, 51 insertions, 0 deletions

diff --git a/scripts/theme-studio/screenshot-previews.sh b/scripts/theme-studio/screenshot-previews.sh
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index 00000000..72894aa7
--- /dev/null
+++ b/scripts/theme-studio/screenshot-previews.sh
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+#!/usr/bin/env bash
+# Screenshot each theme-studio app's page (face table + live preview) headlessly.
+#
+#   ./screenshot-previews.sh OUTDIR [APP ...]
+#   THEME=dupre.json ./screenshot-previews.sh OUTDIR [APP ...]
+#
+# With no APP arguments, shoots every app in the studio. Rides the #preview=<app>
+# hash handler in app.js (the same hash-URL pattern as the browser gates), so the
+# page selects the app itself before Chrome takes the shot. THEME names a theme
+# JSON next to this script (default dupre.json; THEME= empty shoots untitled) so
+# shots show real theme colors -- fresh headless profiles carry no localStorage.
+# Regenerate the page first (make gen) when sources changed; this script shoots
+# what is on disk.
+set -uo pipefail
+
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+OUT="${1:?usage: screenshot-previews.sh OUTDIR [APP ...]}"
+shift || true
+mkdir -p "$OUT"
+
+BROWSER=""
+for b in google-chrome-stable google-chrome chromium chromium-browser; do
+  command -v "$b" >/dev/null 2>&1 && { BROWSER="$b"; break; }
+done
+[ -n "$BROWSER" ] || { echo "no Chromium-family browser found" >&2; exit 1; }
+
+if [ "$#" -gt 0 ]; then
+  APPS="$*"
+else
+  APPS="$(cd "$HERE" && python3 -c 'import generate; print(" ".join(sorted(generate.APPS)))')"
+fi
+
+THEME="${THEME-WIP.json}"
+SUFFIX=""
+if [ -n "$THEME" ]; then
+  [ -f "$HERE/$THEME" ] || { echo "theme not found: $HERE/$THEME" >&2; exit 1; }
+  SUFFIX="&theme=$THEME"
+fi
+
+for app in $APPS; do
+  "$BROWSER" --headless=new --disable-gpu --hide-scrollbars \
+    --allow-file-access-from-files \
+    --window-size=1500,2000 --virtual-time-budget=6000 \
+    --screenshot="$OUT/$app.png" \
+    "file://$HERE/theme-studio.html#preview=$app$SUFFIX" >/dev/null 2>&1
+  if [ -s "$OUT/$app.png" ]; then
+    echo "  shot $app"
+  else
+    echo "  FAILED $app" >&2
+  fi
+done
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