Homepage update & add 3 public lobbies (#3191)

## Description:

Update UI 
check https://homepageupdate.openfront.dev/ 

Improved mobile UI (now fills whole screen for all modals) e.g.:
<img width="432" height="852" alt="image"
src="https://github.com/user-attachments/assets/56de40af-4137-4c57-96b7-3910c9a665b8"
/>

Converted PublicLobby to be "GameModeSelector" to get a nicer 4x4 grid
div, where <GameModeSelector> now handles all the username validation
now (removed redundant code from modals such as matchmaking) also fixed
a bug where someone could have "[XX] X" as thier username (when the
minimum should be 3 chars for their name)

Now visually displays the 3 lobbies ffa/team/special (which is a
continuation from the work done in: #3196 )
<img width="818" height="563" alt="image"
src="https://github.com/user-attachments/assets/a15cd31b-6061-4fb8-83ee-ffde6225cfa7"
/>

updated the background:
<img width="1919" height="807" alt="image"
src="https://github.com/user-attachments/assets/358a7434-51b8-4540-baf2-d1be05053c44"
/>



slightly updated the glassy-look to be less glassy:
<img width="825" height="729" alt="image"
src="https://github.com/user-attachments/assets/1801871b-bbf8-43db-ac53-489337ae80a5"
/>



## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

w.o.n

src/client/components/MainLayout.ts

@@ -19,10 +19,10 @@ export class MainLayout extends LitElement {
   render() {
     return html`
       <main
-        class="relative [.in-game_&]:hidden flex flex-col flex-1 overflow-hidden w-full px-[clamp(1.5rem,3vw,3rem)] pt-[clamp(0.75rem,1.5vw,1.5rem)] pb-[clamp(0.75rem,1.5vw,1.5rem)]"
+        class="relative [.in-game_&]:hidden flex flex-col flex-1 overflow-hidden w-full px-0 lg:px-[clamp(1.5rem,3vw,3rem)] pt-0 lg:pt-[clamp(0.75rem,1.5vw,1.5rem)] pb-0 lg:pb-[clamp(0.75rem,1.5vw,1.5rem)]"
       >
         <div
-          class="w-full max-w-[20cm] mx-auto flex flex-col flex-1 gap-[clamp(1.5rem,3vw,3rem)] overflow-y-auto overflow-x-hidden [scrollbar-width:none] [-ms-overflow-style:none] [&::-webkit-scrollbar]:hidden lg:[scrollbar-width:auto] lg:[-ms-overflow-style:auto] lg:[&::-webkit-scrollbar]:block"
+          class="w-full lg:max-w-[20cm] mx-auto flex flex-col flex-1 gap-0 lg:gap-[clamp(1.5rem,3vw,3rem)] overflow-y-auto overflow-x-hidden"
         >
           ${this._initialChildren}
         </div>