Simplify codebase and fix Enter key on home page

- Enter key now triggers createGame action on home page
- Remove redundant setNickname action from home page
- Remove unused code: join channel, Leave(), Stop() methods
- Consolidate ID generation into game.GenerateID()
- Remove unused CreatedAt field from Game struct

game/store.go

@@ -28,7 +28,7 @@ func NewGameStore() *GameStore {
 }
 
 func (gs *GameStore) Create() *GameInstance {
-	id := generateGameID()
+	id := GenerateID(4)
 	gi := NewGameInstance(id)
 	gs.gamesMu.Lock()
 	gs.games[id] = gi
@@ -44,8 +44,8 @@ func (gs *GameStore) Get(id string) (*GameInstance, bool) {
 	return gi, ok
 }
 
-func generateGameID() string {
-	b := make([]byte, 4)
+func GenerateID(size int) string {
+	b := make([]byte, size)
 	rand.Read(b)
 	return hex.EncodeToString(b)
 }
@@ -55,7 +55,6 @@ type GameInstance struct {
 	gameMu    sync.RWMutex
 	players   map[PlayerID]Syncable
 	playersMu sync.RWMutex
-	join      chan *PlayerSession
 	leave     chan PlayerID
 	done      chan struct{}
 	dirty     bool
@@ -65,7 +64,6 @@ func NewGameInstance(id string) *GameInstance {
 	return &GameInstance{
 		game:    NewGame(id),
 		players: make(map[PlayerID]Syncable),
-		join:    make(chan *PlayerSession, 5),
 		leave:   make(chan PlayerID, 5),
 		done:    make(chan struct{}),
 	}
@@ -101,10 +99,6 @@ func (gi *GameInstance) Join(ps *PlayerSession) bool {
 	return true
 }
 
-func (gi *GameInstance) Leave(pid PlayerID) {
-	gi.leave <- pid
-}
-
 func (gi *GameInstance) GetGame() *Game {
 	gi.gameMu.RLock()
 	defer gi.gameMu.RUnlock()
@@ -186,7 +180,3 @@ func (gi *GameInstance) publish() {
 		sync.Sync()
 	}
 }
-
-func (gi *GameInstance) Stop() {
-	close(gi.done)
-}