harness: safari mode (WebKit over safaridriver, real activation)

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01K6897PWcUEwHiqZMcVnNF6

tools/harness.sh

@@ -14,6 +14,7 @@ MODE=${1:-loop}
 case "$MODE" in
   loop) FRAG=tools/harness.html; AUTOPLAY=--autoplay-policy=no-user-gesture-required ;;
   resume) FRAG=tools/harness-resume.html; AUTOPLAY= ;;
+  safari) exec python3 tools/harness-safari.py tools/harness.html "${2:-90}" ;;   # WebKit, after `safaridriver --enable` once
   *) echo "usage: sh tools/harness.sh [resume]" >&2; exit 2 ;;
 esac
 CHROME=${CHROME:-}