feat: add snake multiplayer chat as sidebar with vivid player colors

Move chat to the right of the board using a flex wrapper that stacks
vertically on narrow screens. Restore original snake player colors by
removing the desaturation filter added with the dark theme.

main.go

@@ -6,9 +6,12 @@ import (
 	"database/sql"
 	_ "embed"
 	"encoding/hex"
+	"encoding/json"
 	"log"
 	"net/http"
 	"os"
+	"sync"
+	"time"
 
 	"github.com/google/uuid"
 	"github.com/joho/godotenv"
@@ -588,8 +591,51 @@ func main() {
 			}
 		})
 
+		chatMsg := c.Signal("")
+		var chatMessages []ui.ChatMessage
+		var chatMu sync.Mutex
+
+		sendChat := c.Action(func() {
+			msg := chatMsg.String()
+			if msg == "" || si == nil {
+				return
+			}
+			slot := si.GetPlayerSlot(playerID)
+			if slot < 0 {
+				return
+			}
+			cm := ui.ChatMessage{
+				Nickname: si.GetGame().Players[slot].Nickname,
+				Slot:     slot,
+				Message:  msg,
+				Time:     time.Now().UnixMilli(),
+			}
+			data, err := json.Marshal(cm)
+			if err != nil {
+				return
+			}
+			c.Publish("snake.chat."+gameID, data)
+			chatMsg.SetValue("")
+		})
+
 		if gameExists {
 			c.Subscribe("snake."+gameID, func(data []byte) { c.Sync() })
+
+			if si.GetGame().Mode == snake.ModeMultiplayer {
+				c.Subscribe("snake.chat."+gameID, func(data []byte) {
+					var cm ui.ChatMessage
+					if err := json.Unmarshal(data, &cm); err != nil {
+						return
+					}
+					chatMu.Lock()
+					chatMessages = append(chatMessages, cm)
+					if len(chatMessages) > 50 {
+						chatMessages = chatMessages[len(chatMessages)-50:]
+					}
+					chatMu.Unlock()
+					c.Sync()
+				})
+			}
 		}
 
 		// Auto-join if nickname exists
@@ -638,7 +684,25 @@ func main() {
 			)
 
 			if sg.Status == snake.StatusInProgress || sg.Status == snake.StatusFinished {
-				content = append(content, ui.SnakeBoard(sg))
+				board := ui.SnakeBoard(sg)
+
+				if sg.Mode == snake.ModeMultiplayer {
+					chatMu.Lock()
+					msgs := make([]ui.ChatMessage, len(chatMessages))
+					copy(msgs, chatMessages)
+					chatMu.Unlock()
+					chat := ui.SnakeChat(msgs, chatMsg.Bind(), sendChat.OnClick(), sendChat.OnKeyDown("Enter"))
+					content = append(content, h.Div(h.Class("snake-game-area"), board, chat))
+				} else {
+					content = append(content, board)
+				}
+			} else if sg.Mode == snake.ModeMultiplayer {
+				// Show chat even before game starts (waiting/countdown)
+				chatMu.Lock()
+				msgs := make([]ui.ChatMessage, len(chatMessages))
+				copy(msgs, chatMessages)
+				chatMu.Unlock()
+				content = append(content, ui.SnakeChat(msgs, chatMsg.Bind(), sendChat.OnClick(), sendChat.OnKeyDown("Enter")))
 			}
 
 			// Only show invite link for multiplayer games