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/HelpModal.ts

@@ -99,14 +99,10 @@ export class HelpModal extends BaseModal {
     const keybinds = this.keybinds;
 
     const content = html`
-      <div
-        class="h-full flex flex-col ${this.inline
-          ? "bg-black/60 backdrop-blur-md rounded-2xl border border-white/10"
-          : ""}"
-      >
+      <div class="${this.modalContainerClass}">
         ${modalHeader({
           title: translateText("main.help"),
-          onBack: this.close,
+          onBack: () => this.close(),
           ariaLabel: translateText("common.back"),
         })}