feat: maximize sorter demo realism and add safe agent MVP

Wire live classifyItem into continuous playback, add jam/E-stop cases,
presenter controls (seek/speed/hotkeys), quality modes, demo scripts,
audit docs, and a verify-only autonomous agent CLI with hard safety limits.

Co-authored-by: Cursor <cursoragent@cursor.com>

scripts/demo-stop.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+set -euo pipefail
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+PID_FILE="${ROOT}/.demo-preview.pid"
+if [[ -f "$PID_FILE" ]]; then
+  pid="$(cat "$PID_FILE")"
+  if kill -0 "$pid" 2>/dev/null; then
+    kill "$pid" || true
+    echo "[demo-stop] stopped pid $pid"
+  fi
+  rm -f "$PID_FILE"
+else
+  echo "[demo-stop] no preview pid file"
+fi
+pkill -f "vite preview --host 127.0.0.1 --port 3101" 2>/dev/null || true