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

ui/lobby.go

@@ -4,7 +4,7 @@ import (
 	"github.com/ryanhamamura/via/h"
 )
 
-func LobbyView(nicknameBind, setNicknameKeyDown, createGameClick h.H) h.H {
+func LobbyView(nicknameBind, createGameKeyDown, createGameClick h.H) h.H {
 	return h.Main(h.Class("container"),
 		h.Div(h.Class("lobby"),
 			h.H1(h.Text("Connect 4")),
@@ -18,7 +18,7 @@ func LobbyView(nicknameBind, setNicknameKeyDown, createGameClick h.H) h.H {
 						h.Placeholder("Enter your nickname"),
 						nicknameBind,
 						h.Attr("required"),
-						setNicknameKeyDown,
+						createGameKeyDown,
 					),
 				),
 				h.Button(