Update homepage & in-game promos (#3602)

## Description:

* Replace the static footer ad (HomeFooterAd component) with a Playwire
bottom_rail ad that loads on lobby join and persists into the spawn
phase
* Expand in-game ad slots from 1 to 3 (standard_iab_left1, left3, left4)
with a timer-based visibility check to show a background container when
ads render
* Remove the resize-based footer ad height logic and gutter ad vertical
offset adjustments that depended on it

<img width="1828" height="961" alt="Screenshot 2026-04-16 at 12 14
00 PM"
src="https://github.com/user-attachments/assets/50bfd0de-dd54-4f8b-b75e-04b720a1841b"
/>


<img width="1286" height="939" alt="Screenshot 2026-04-16 at 11 59
18 AM"
src="https://github.com/user-attachments/assets/e0fb0762-82e7-444f-8706-5908aad0f094"
/>
## 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:

evan

index.html

@@ -26,6 +26,11 @@
         padding-left: env(safe-area-inset-left);
       }
 
+      /* Prevent Playwire bottom rail from affecting flex layout */
+      [id^="pw-oop-bottom_rail"] {
+        position: fixed !important;
+      }
+
       /* Ensure full viewport height on iOS */
       html,
       body {
@@ -257,9 +262,7 @@
         ></ranked-modal>
       </main-layout>
 
-      <!-- Ad above footer -->
       <div class="[.in-game_&]:hidden mt-auto flex flex-col shrink-0">
-        <home-footer-ad></home-footer-ad>
         <page-footer></page-footer>
       </div>