Update sandbox schema, DB, and web
- Add ports array to sandbox lexicon and TypeScript types (ints 1–65535,
max 100)
- Add migration 0009 that provides base62_encode and sandbox_id() (sbx_
prefix)
- Add generated snapshot and journal entry for migration
- Add @xterm/xterm to web dependencies
- Minor web UI tweaks: Stop Sandbox button, AT Protocol link, and remove
unused import