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>

.gitignore

@@ -7,3 +7,7 @@ vite.config.d.ts
 .env.*
 npm-debug.log*
 input_info/extracted/
+agent/state/
+agent/reports/
+.demo-preview.pid
+.demo-preview.log