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/styles.css

@@ -57,8 +57,24 @@ body {
   -webkit-box-sizing: border-box;
   -moz-box-sizing: border-box;
   box-sizing: border-box;
-  scrollbar-width: auto;
-  scrollbar-color: rgba(255, 255, 255, 0.2) transparent;
+}
+
+/* Hide scrollbar on mobile, show on larger screens */
+@media (max-width: 1023px) {
+  * {
+    scrollbar-width: none;
+    -ms-overflow-style: none;
+  }
+  ::-webkit-scrollbar {
+    display: none;
+  }
+}
+
+@media (min-width: 1024px) {
+  * {
+    scrollbar-width: auto;
+    scrollbar-color: rgba(255, 255, 255, 0.2) transparent;
+  }
 }
 
 /* Add custom scrollbar styles */
@@ -66,6 +82,13 @@ body {
   width: 12px;
 }
 
+@media (min-width: 1024px) {
+  ::-webkit-scrollbar {
+    width: 12px;
+    display: block;
+  }
+}
+
 ::-webkit-scrollbar-track {
   background: transparent;
   border-radius: 4px;