refactor(ui): migrate tailwindcss v3 to v4 (#2735)

## Description:

migrate tailwindcss v3 to v4

## 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:

wraith4081

---------

Co-authored-by: iamlewis <lewismmmm@gmail.com>
Co-authored-by: Ryan <7389646+ryanbarlow97@users.noreply.github.com>

src/client/StatsModal.ts

@@ -91,7 +91,7 @@ export class StatsModal extends LitElement {
         <div class="flex flex-col items-center justify-center p-6 text-white">
           <p class="mb-4 text-center">${this.error}</p>
           <button
-            class="px-4 py-2 bg-blue-600 hover:bg-blue-700 rounded text-sm font-medium"
+            class="px-4 py-2 bg-blue-600 hover:bg-blue-700 rounded-sm text-sm font-medium"
             @click=${() => this.loadLeaderboard()}
           >
             Retry
@@ -222,10 +222,10 @@ export class StatsButton extends LitElement {
     }
 
     return html`
-      <div class="fixed top-20 right-4 z-[9998]">
+      <div class="fixed top-20 right-4 z-9998">
         <button
           @click="${this.open}"
-          class="w-12 h-12 bg-blue-600 hover:bg-blue-700 text-white rounded-full shadow-2xl hover:shadow-3xl transition-all duration-200 flex items-center justify-center text-xl focus:outline-none focus:ring-4 focus:ring-blue-500 focus:ring-offset-4"
+          class="w-12 h-12 bg-blue-600 hover:bg-blue-700 text-white rounded-full shadow-2xl hover:shadow-2xl transition-all duration-200 flex items-center justify-center text-xl focus:outline-hidden focus:ring-4 focus:ring-blue-500 focus:ring-offset-4"
           title="${translateText("stats_modal.title")}"
         >
           <img src="/icons/stats.svg" alt="Stats" class="w-6 h-6" />