docs: add publishing mancala.js to the TODO

The apps use the engine from the repo, so publishing the fixed engine to
npm is left as the last deployment step.

TODO.md

@@ -74,6 +74,8 @@ See `docs/specs/web-redesign`.
 - [ ] Back up the Postgres volume (Keycloak and saved games), e.g. a daily `pg_dumpall`
 - [ ] Set `MANCALA_DB_PASSWORD` and `POSTGRES_PASSWORD` in `apps/.env` on the server; the `postgres` volume replaces
       `keycloak-db`, so Keycloak starts with a fresh database there
+- [ ] Last step: publish a new `mancala.js` to npm (it is at `0.0.2-beta.3` from 2022), so the published engine skips
+      the opponent's store when sowing. The apps do not need it; they use `packages/mancala.js` through `link:`
 
 ## Security