feat(stats): expose the achievement code on profile and leaderboard rows

[diangogav]

Depends on diangogav/evolution-types#16 (the src/evolution-types pointer moves to its head commit, which adds achievements.code).

Summary

• achievements[] items on GET /users/:userId/stats and GET /stats carry code: the stable key of a gameplay achievement awarded by the game server (first_win, wins_10, format_first_win:Edison, ...), null for admin tournament trophies.
• UserAchievementSchema, the UserAchievement domain object and the domain doc gain the field; both jsonb_build_object builders select a.code.

Read side of the automatic achievements feature (game server: diangogav/EDOpro-server-ts#405; client follow-up hides "0 pts" for gameplay rows).

Test plan

• bun run lint
• bun test (521 passed)
• bun run build
• After the migration on dev: GET /api/v1/users/<id>/stats shows code on each achievement