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

go.sum

@@ -8,10 +8,6 @@ github.com/andybalholm/brotli v1.2.0/go.mod h1:rzTDkvFWvIrjDXZHkuS16NPggd91W3kUS
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/go-via/via v0.1.4 h1:Fz9fwaT5+TBqcetiVM33SxkuysAeFDOiiASFu3GW7WY=
-github.com/go-via/via v0.1.4/go.mod h1:Y8oddRwP6SWX15Xb6UQj4HtLZwxTYI1HbWBmELtB/f8=
-github.com/go-via/via-plugin-picocss v0.1.1 h1:rbA9wL9eEanT8HOOfX1b4Mr2L2VjaDrsIrUECDxV73k=
-github.com/go-via/via-plugin-picocss v0.1.1/go.mod h1:npvsvG2FWeIPkzHzSSzW+uBGE0m5gnIAdlePqKcfuAQ=
 github.com/google/brotli/go/cbrotli v0.0.0-20230829110029-ed738e842d2f h1:jopqB+UTSdJGEJT8tEqYyE29zN91fi2827oLET8tl7k=
 github.com/google/brotli/go/cbrotli v0.0.0-20230829110029-ed738e842d2f/go.mod h1:nOPhAkwVliJdNTkj3gXpljmWhjc4wCaVqbMJcPKWP4s=
 github.com/klauspost/compress v1.16.7/go.mod h1:ntbaceVETuRiXiv4DpjP66DpAtAGkEQskQzEyD//IeE=