feat: add configurable speed and expanded grid presets for snake

- Add per-game speed setting with presets (Slow/Normal/Fast/Insane)
- Add speed selector UI in snake lobby
- Expand grid presets with Tiny (15x15) and XL (50x30)
- Auto-calculate cell size based on grid dimensions
- Preserve speed setting in rematch games

main.go

@@ -152,6 +152,19 @@ func main() {
 			snakeNickname = c.Signal(username)
 		}
 
+		// Speed selection signal (index into SpeedPresets, default to Normal which is index 1)
+		selectedSpeedIndex := c.Signal(1)
+
+		// Speed selector actions
+		var speedSelectClicks []h.H
+		for i := range snake.SpeedPresets {
+			idx := i
+			speedSelectClicks = append(speedSelectClicks, c.Action(func() {
+				selectedSpeedIndex.SetValue(idx)
+				c.Sync()
+			}).OnClick())
+		}
+
 		// Snake create game actions — one per preset for solo and multiplayer
 		var snakeSoloClicks []h.H
 		var snakeMultiClicks []h.H
@@ -163,7 +176,12 @@ func main() {
 					return
 				}
 				c.Session().Set("nickname", name)
-				si := snakeStore.Create(w, ht, snake.ModeSinglePlayer)
+				speedIdx := selectedSpeedIndex.Int()
+				speed := snake.DefaultSpeed
+				if speedIdx >= 0 && speedIdx < len(snake.SpeedPresets) {
+					speed = snake.SpeedPresets[speedIdx].Speed
+				}
+				si := snakeStore.Create(w, ht, snake.ModeSinglePlayer, speed)
 				c.Redirectf("/snake/%s", si.ID())
 			}).OnClick())
 			snakeMultiClicks = append(snakeMultiClicks, c.Action(func() {
@@ -172,28 +190,35 @@ func main() {
 					return
 				}
 				c.Session().Set("nickname", name)
-				si := snakeStore.Create(w, ht, snake.ModeMultiplayer)
+				speedIdx := selectedSpeedIndex.Int()
+				speed := snake.DefaultSpeed
+				if speedIdx >= 0 && speedIdx < len(snake.SpeedPresets) {
+					speed = snake.SpeedPresets[speedIdx].Speed
+				}
+				si := snakeStore.Create(w, ht, snake.ModeMultiplayer, speed)
 				c.Redirectf("/snake/%s", si.ID())
 			}).OnClick())
 		}
 
 		c.View(func() h.H {
 			return ui.LobbyView(ui.LobbyProps{
-				NicknameBind:      nickname.Bind(),
-				CreateGameKeyDown: createGame.OnKeyDown("Enter"),
-				CreateGameClick:   createGame.OnClick(),
-				IsLoggedIn:        isLoggedIn,
-				Username:          username,
-				LogoutClick:       logout.OnClick(),
-				UserGames:         userGames,
-				DeleteGameClick:   deleteGame,
-				ActiveTab:         activeTab.String(),
-				TabClickConnect4:  tabClickConnect4.OnClick(),
-				TabClickSnake:     tabClickSnake.OnClick(),
-				SnakeNicknameBind: snakeNickname.Bind(),
-				SnakeSoloClicks:   snakeSoloClicks,
-				SnakeMultiClicks:  snakeMultiClicks,
-				ActiveSnakeGames:  snakeStore.ActiveGames(),
+				NicknameBind:       nickname.Bind(),
+				CreateGameKeyDown:  createGame.OnKeyDown("Enter"),
+				CreateGameClick:    createGame.OnClick(),
+				IsLoggedIn:         isLoggedIn,
+				Username:           username,
+				LogoutClick:        logout.OnClick(),
+				UserGames:          userGames,
+				DeleteGameClick:    deleteGame,
+				ActiveTab:          activeTab.String(),
+				TabClickConnect4:   tabClickConnect4.OnClick(),
+				TabClickSnake:      tabClickSnake.OnClick(),
+				SnakeNicknameBind:  snakeNickname.Bind(),
+				SnakeSoloClicks:    snakeSoloClicks,
+				SnakeMultiClicks:   snakeMultiClicks,
+				ActiveSnakeGames:   snakeStore.ActiveGames(),
+				SelectedSpeedIndex: selectedSpeedIndex.Int(),
+				SpeedSelectClicks:  speedSelectClicks,
 			})
 		})
 	})