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

ui/snakelobby.go

@@ -7,7 +7,7 @@ import (
 	"github.com/ryanhamamura/via/h"
 )
 
-func SnakeLobbyTab(nicknameBind h.H, soloClicks, multiClicks []h.H, activeGames []*snake.SnakeGame) h.H {
+func SnakeLobbyTab(nicknameBind h.H, soloClicks, multiClicks []h.H, activeGames []*snake.SnakeGame, selectedSpeedIndex int, speedSelectClicks []h.H) h.H {
 	// Solo play buttons
 	var soloButtons []h.H
 	for i, preset := range snake.GridPresets {
@@ -56,6 +56,29 @@ func SnakeLobbyTab(nicknameBind h.H, soloClicks, multiClicks []h.H, activeGames
 		),
 	)
 
+	// Speed selector
+	var speedButtons []h.H
+	for i, preset := range snake.SpeedPresets {
+		btnClass := "btn btn-sm"
+		if i == selectedSpeedIndex {
+			btnClass += " btn-active"
+		}
+		var click h.H
+		if i < len(speedSelectClicks) {
+			click = speedSelectClicks[i]
+		}
+		speedButtons = append(speedButtons, h.Button(
+			h.Class(btnClass),
+			h.Type("button"),
+			h.Text(preset.Name),
+			click,
+		))
+	}
+	speedSelector := h.Div(h.Class("mb-4"),
+		h.Label(h.Class("label"), h.Text("Speed")),
+		h.Div(append([]h.H{h.Class("btn-group")}, speedButtons...)...),
+	)
+
 	soloSection := h.Div(h.Class("mb-6"),
 		h.H3(h.Class("text-lg font-bold mb-2"), h.Text("Play Solo")),
 		h.Div(append([]h.H{h.Class("flex gap-2 justify-center")}, soloButtons...)...),
@@ -93,6 +116,7 @@ func SnakeLobbyTab(nicknameBind h.H, soloClicks, multiClicks []h.H, activeGames
 
 	return h.Div(
 		nicknameField,
+		speedSelector,
 		soloSection,
 		multiSection,
 		gameListEl,