- Store shape listener refs in Map, remove in unregisterShape() (critical leak)
- Compact Automerge history every 500 changes via clone() to cap WASM heap
- Clean shapeLastPos entries on shape removal
- Store outside-click handler ref, clean up in disconnectedCallback()
- Cap MI messages at 50 and prompt messages at 30 to prevent unbounded growth
- Store keep-alive interval handle
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>