// Package game is the backend's game domain. It drives the in-process
// scrabble-solver engine (internal/engine) over a single match and owns
// everything the engine deliberately does not: persistence, scheduling and the
// player-facing operations.
//
// Active games are event-sourced. Durably, a game is its games row plus an
// append-only, dictionary-independent move journal (game_moves); the live
// position is an engine.Game kept warm in an in-memory cache and rebuilt by
// replaying the journal on a cache miss, which the engine's seeded bag makes
// exact (docs/ARCHITECTURE.md §9). Each game is serialised by a per-game lock,
// since engine.Game is not safe for concurrent use; on a persistence failure the
// live game is evicted so the next access rebuilds from the journal.
//
// The Service exposes create, the play/pass/exchange/resign transitions with
// validate-at-submit scoring, the one-per-game-plus-wallet hint, the unlimited
// word-check tool with complaint capture, per-player game state, history and GCG
// export, and the per-game turn-timeout sweeper that auto-resigns an overdue
// player (honouring their daily away window). The HTTP surface that fronts these
// operations is added with the gateway in a later stage.
package game